Handbook_of_ethological_methods

Prévia do material em texto

Handbook of ethological methods
SECOND EDITION
PHILIP. N. LEHNER
Depdrtmenl of Biology, Colorado Stote Universiry
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Contents
Prefoce
INTRODUCTION
What is ethology?
Why study animal behavior?
What to study?
l.j.l l*vels oJ behovior
1.j.2 Areasofstudy
l.j.j Categorics of questiore
1.4 Scientific method
t.s Ethological approach
1.6 Descriptive versus experimental research
I GETTING STARTED
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1.2
1.3
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2 A CONCEPTUAL MODEL OF ANIMAL BEHAYIOR
2.1 Continuous stream of behavior
z.z Predisposition to behave: dilfering contributions
2.2.1 Genotype, envircnmenl (experience) ond htemction
2.2.2 Anotomyond physiology
2.3 A model for a behavioral act
2.3.1 The mimol
2.3.2 Stimuli
2.3.3 Behavior
2.3.1 Ethologicol model ol innate behavior
2.i.5 Associotive learning paradigms
2.3.6 Feedbock
2.3.7 Feedlorword
2,4 Application of the model
2.1,1 Cancuptuallzlng the oreos ol study
2,1,2 OrynkW thc typcs of questioa
2,1,t Focuhgrutorch
2,11 Dowhpht an .xpanM ot mon locutd nobl
,,1t Dlqfit st tnlr,lI, tfu ltchst h otlmb
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2.5 Summary
3 CHOICE OF SUBJECTS
3.1 Species-oriented research
3.2 Concept-oriented research
3-2.1 August Krogh principle
3.2.2 Suitobility verus owilobility
4 RECONNAISSANCE OBSERVATION
4.1 How to observe
4.1. I Walching versus obreming
4.1.2 An exercbe in obserting
4.1.3 Fieldnotes
4.1.4 Equipment
-- 4.2 How to describe behavior
' 4.2.1 Empirical versuslunctionoldescriplions
4.2.2 Cotalog, repertoire md elhogrom
4.3 Information resources
4.3.1 Literature
4.3.2 Otherresearchers
4.3.3 Films ond videotapes
5 DELINEATION OF RESEARCH
5.1 Conceptualizingtheproblem
5.1.1 Whal are the questions?
5.L2 Statingobjectives
5.1.3 Research hypotheses
5.2 Using the model for a behavioral act
DESIGN OF RESEARCH
Description versus experimentation
Variables
Behavior units
6.3.1 Classifcation of behavior unils
6.3.2 Spotial and lemporal aspecls
6.3.3 Descriptions and definitions of behavior unils
6.3.4 Number of behavioral units to meosure
6.3.5 Volidity
Rescarchcr-statistician
Barlc oxpcrimcntd doltnl
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6.1
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6.4
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6.5.2 Experimmtal designs
6.5,3 Rondom, haphazord and oppoilunistic samples
6.6 Relative efficiency of experimental designs
6.7 Determination of sample size
7 EXPERIMENTAL RESEARCH
z.l Thevaryingvariables
7.1.1 Noturol variation
7. 1,2 Artificial manipulation
7.2 Further examples of experimental manipulation
7.2.1 In thefield
7.2.2 In the laborotory
z.r Field to laboratory: a continuum
II COLLECTING THE DATA
8 DATA COLLECTION METHODS
8. t Research desigrr and data collection
8.2 Scales of measurement
8.3 Sampling methods
-8.3.1 
Focal-animal (pair, group) versus all-animal samplhg
8.3.2 Adlibit':um sampling
8,3.3 Continuow recording sampling methods
E,3.4 Time sampling
8.3.5 Summory
8.4 Observereffects
8.5 Reliability
E,5. I Intro-obrner or sef-reliability
E,5.2 Inter-observer reliability
t,6 ldentification and naming of individuals
E.6.1 Noturolmarks
8.6.2 Copture and marking
E.6.3 Assigunent of numbers and natnes
DATA.COLLECTION EQUIPMENT
Notobook and pcncil
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CONTENTS
9.3 Clocks and counters
9.4 Calculators
9.5 Strip-chart event recorders
9.6 Stenograph
9.7 Computer-compatible data loggers
9.8 Microcomputers
981 Datacollection
9.8 2 Dala storage and manipulution
9.9 Audio-taperecorders
9.9. I Dato collection on uudio-tape recordcrs
9.9 2 Recording unimol sounds
9.9 3 Playback of sounds
9 9.4 Ultrasonic delectors
9.lo Analysis of animal sounds
9 I0.l Equipment
9 l0 2 Analysis of sound spectrograms
9. l0 j Computer analysis of recorded sounds
9.1 I Photography
9 I l.l Still photogruphy
9.ll 2 Motion-picture photogruphy
9.ll 3 Filmanalysis
9.12 Videotape recording and analysis
9.13 Stopwatches
9.14 Metronomes
9 l5 Determining geographic location
9 l5.l Global Positioning System and Argos Satellite System
9 l5 2 Biotelemetry
IO SELECTED EXAMPLES OF DATA COLLECTION
AND DESCRIPTION
lo.l Individualbehavior
l0 I 1 Terreslriql tetrupod loc.omolion
10.2 Social behavior
10.2 I Disploys
l0 2.2 Dominant-suhordinate relutionships
l0 2.3 So<.iol orguni:ation
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CONTENTS
III ANALYZING THE RESULTS
II INTRODUCTION TO STATISTICAL ANALYSES
I l.l Statistical principles
ll 2 Statisticalhypotheses
ll 3 Hypothesis testing
I 1.4 Type I and type II errors
I I 5 Selecting the alpha level
ll 6 Poweroiatest
I 1.7 Sample statistics
I I 7.1 Sample disttibutions
I I 7.2 Sumple mean, mode und median
I I 7.3 Skevness
I I 7.4 Location
I I 7.5 Variubilily
I 1 7.6 Standard deviation
I I 7.7 Sample mean confdence interval
I I 7.8 CoeJfcient of voriation
12 SELECTION OF A STATISTICAL TEST
I I I Parametric versus nonparametric statistical tests
12 I I Paramelrictesls
l2 I 2 Datu lranslbrmalions
12 I 3 Nonpurumelrictests
I.I PARAMETRIC STATISTICAL TESTS
lr I Completely randomized design
l-1 I I Ttro indcpcndent sumples
l -1 I 2 Thrta or ttrorc indepcnclent sumples
I I I Randomized block, matched pairs or repeated measures design
l-l ) I Ttn rtlutcd or nul<hed sumples
14 NONPARAMETRIC STATISTICAL TESTS
l.l I (irnplctcly rantlomizcd design
ll I I (hx,vrriuhlr
14 l) l\t,nriililtt
l.l ,t Rlrttkrlizctl block, nurtchcd pairs lnd rcpcatcd mcasurcs design
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xlv CONTENTS
15 RATES OF BEHAVIOR AND ANALYSIS OF
SEQUENCES
l5.l Ratesofbehavior
15.2 Analysis of sequences
15.2.1 Intro-individual sequences
I 5.2.2 Inter-individual sequences
16 MULTIVARIATE ANALYSES
16.l Matric€s
16.2 Grouping behaviors
16.3 Grouping individuals
16.4 Describing differences among individuals
16.5 Discriminating among groups of individuals or behaviors
16.6 Analyzing sequences of behavior
16.6.1 Faclor analysis
16.6.2 Multidimensional scaling
16.7 Summary
16.8 Software packages for statistical analyses
I7 SPATIAL ORIENTATION AND TIME: CIRCULAR
STATISTICS AND SPATIAL PATTERNS
17.l Tests for randomness of directions (or times)
I 7. 1. I Chi-square goodness-of-fit test
17.1.2 Rayleigh test
17.1.3 Y test
17.2 Difference between sample mean direction (or time period) and specified
direction (or specified time period)
17.2.1 Smtple mean direction
17.2.2 Confidence interyal
17.3 Difference in sample mean directions between two, or morg groups of
animals
l7.j.l Two smtple runs test
17.3.2 llatsorlhlliams two somple test
1 7. 3.3 llatson-lAiilhms mull isample lest
I 7.4 Spatial patterns: animal-animal and animal-<nvi ronment
1 7.4. I Animal<nimol spatiol relationships
I 7.4.2 Animal<nvironmenl spatial rclotionships
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CONTENTS
18 INTERPRETATION AND PRESENTATION OF
RESULTS
l8.l What do your results mean?
18.2 Visual representations
18.2.1 Graphs andfigures
18.2.2 Vector diagrams
18.2.3 Kinematic graphs
18.2.4 Conceptual models
18.2.5 Other illusuations
18.3 Comparisons with previous results
18,4 Re-evaluation
I 8.5 Revising and restating hypothesesAPPENDICES
A Statistical figures and tables
Table AL Factorials. Values oft!
Toble A2. Lagarilhms oflactorials lor n* I to 199
Table A3. Binomial coelficients
Table A4. Critical valuesfor the F-Max test lor homogeneily of tariance
Table A5. Critical values of the t-stalisticlot o two'railed test
Table A6,. Critical values ofF for the onolysis of variance Alpho:0-05
Tbble A6, Criticol values o;[F for the analysis of variance. Alpho=0.01
Table A7. Criticol values for signifcance of the Pearson producl momenl correlalion
coelficient r, 551
Table A8,. Crilical values of r for the one-sample and two-sample runs test. Alpha=0.05 552
Table A8r. Critical values of r for lhe one-sample runs tesl 553
Thbte A9. Crilicol values of the chi-square distibutionfor one'tailed tests 554
Table Al0. Critical values ollJ for the Mann-Whilney test 555
Thble Al I. Critical voluesfor the Kolmogorov-Smirnov two-samPle, one-toiled tesl lot
small samples
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Toble A12- Critical values for the Kolmogorov-Smimov twosample, lw4ailed rcsr lor
nall samples 560
Table A I 3. C r il ico I vo I ue s for t he Kolmogorov-Sm bnot two-sample,, wo- lo iled t e s I lor
large samples 5U
Table A14. Critical valuesfor the Kruskal-Wallis one'way analysis of variance 555
Tabte AI5. Crilical values of Qfor Dunn's multiple comParison test 567
Table Al6, Critical values ol Slor Kendoll's Coe!ficienl ol Concordancefor small samples 568
Table At7, Probobilitieslor the two-tailedsign test 569
Table AlE. Criticul volues of Tfor lhe l{ilcoxon malched-pairs signed-ronks test 570
Tobte Al9. Critical volues of Spearman's Mo correlotion coefficient 571
Thble A20. Critical volues ol Kendoll's tau correlation coelficient 57f
Table A2!, Crlticul valuesoftllot Dunnctt's test 574
Tabls A22, Valucsoflogrnond -plogrp 576
Mlt A2t, Valutt ol ilna cotlnc und tangcnl lor dhectlon and time 578
lbbLA2l,Crltl(g,lwlwtofttlorthtY tttt 5E9
a'
t Introduction
One does not meet oneself until one catches the reflection from an eye
other than human. IEiseley, 1964:24]
ln choosing to study the behavior of animals you are setting off on a voyage across
wuters that are often rough and, in some areag poorly charted. This book is basi-
ctlly a compilation of practical information that is intended to help smooth the
wutcrs and assist you in charting your course. I have taken the liberty of infusing it
with personal and borrowed philosophy. These philosophical interludes are meant
lo $ment together concrete blocks of facts and invite you to stop and ponder what
you have learned and what it means.
The most disheartening (and sometimes disarming) question that an uninitiated
clhologist can face is: 'So what?'You can be confronted with that question at techni-
crl meetings or cocktail partieq and answers vary from informative discourses to
ohlcene threats. I hope that some of the discussions found in this book help you to
wrcctle with that question.
The study of behavior encompasses all of the movements and sensations
by which animals and men mediate their relationships with their
external environments - physical, biotic and social. No scientific field is
more complex, and none is more central to human problems and
aspirations. IAlexander, 1975:77]
Onc of the greatest challenges you face is to keep your own studies of animal
hchrvior in perspective. Why did you choose that particular species or concept to
rludy (lcctions 1.4, 2.1, 2.2)?What is the focus of your study? Three dimensions of
lhrr qucstions are discussed in section 1.3, below. What is already known about the
tubjcct (roction 4.3)? Are you replicating someone else's research, testing someone
rll0l hypothcsig, or ar€ you answering your own questions? Will your results be
llmltod to tho individuals you are observing or will you consider them a representa-
llw rrmplo of a lrrgor population?
Errllcr I uld thrt tho rtudy of animal behavior is a fascinating voyage; remem-
hr to oontlotully mru whotu you arg wherc you havc bcen, and where you are
tolnl,
INTRODUCTION
I.I WHAT IS ETHOLOGY?
Everyone seems to have their own definition of ethology, although a precise and
widely accepted deflnition eludes ethologists. A verbal exchange among Konrad
Lorenz, Niko Tinbergen, Theodore Schneirla and others on the definition of ethol-
ogy makes interesting history and reading (Schaffner 1955l'77-78). Eisner and
Wilson ( 1975:1) deflne ethology as the:
. . . study of whole patterns of animal behavior under natural
conditions, in ways that emphasize[d] the functions and the evolutionary
history of the patterns.
However, for our purposes, let us focus on Lorenz's ( 1960a) definition: 'Ethology
can be briefly defined as the application of orthodox biological methods to the
problems of behavior'. As a basis for this definition, Lorenz (op. cit.) described the
geneologyofethologyasfollows: '...biology...isitsmother.'.whereas...fora
father, a very plain zoologist Charles Darwin'. Ethology's heritage should be kept
firmly in mind.
Ethology is a nearly limitless discipline which operates basically along the three
dimensions illustrated in Figure l.l. These are continuous dimensions along which
studies can be focused.
I.2 WHY STUDY ANIMAL BEHAVIOR?
Reasons for studying animal behavior might emphasize either obtaining or apply-
ing knowledge. Drickamer and Vessey (1992) listed some of the reasons we study
animal behavior:
t Curiosity about the living world.
2 Learn about relationships between animals and their environments'
I Establish general principles common to all behavior'
4 Better understand our own behavior.
s Desire to preserve and maintain the environment.
6 Conserve and protect endangered species.
7 Control economically costly animal pests.
When asked why she became an ethologist, Jane Goodall replicd'curiosity'
(Anonymous, 1988). Curiosity probably rlrivcs most cthologists, bttt itt ortlcr to gct
a brgader perspcctivc on thc qucstion I rccot'tttttctttl pcrtrsirtg l)cwshtrry's ( lt)ti51
conrpilatiott ol'tlrc ittttobiogrlphics ol' |() wcll ktlowtt clllologisls.
WHAT TO STUDY?
ilACRO
ltttolYloae I
leBoReT0Rr
(highly controlled)
8p60
arc
(cellular)
l:ig. I I Three dimensions of ethology (drawing by Brenda Knapp).
I3 WHAT TO STUDY?
I trr some researchers this question is seemingly unimportant slnce they have fixed
rnost ol their attention on a chosen species. Choice of species, however, is only a
pru tiul answer to the question: 'What to study?'Others want to emulate the media's
l)()rtriryals of Dian Fossey, Jane Coodall, Konrad Lorenz, and Niko Tinbergen.
I lrcy do not really care what they study as long as it is adventurous. However, what
rr prcscrrted in an hrlur-long television program about an ethologist's research are
rlre lrighlights ol'thousands of hours of data collection. Powers (1994), while dis-
( u\silrg ol' thc positivc impact ol' television on the environmental movement,
,,1Ir'rctl thc lirllowing. sotnewhat overstated assessment:
. . . TV progllrtrs tcnrl to distort nature's rhythms and interactions, to
srry rrothirrg ol its scopc urrtl tlivcrsity. Arlimals in the wild are mostly
rncr t strrrrrirrg or groorrring tlrcrnsclvcs. Tclcvision abhors inertia. Thus,
cvcn tlrc grrorl shows tllirsticirlly ctlit lrtttl crttrtlcttsc thc movctttcnt
l)itllcnts ol irrrrrrrirls to tlrc poittl whctc, its rttrtlrol llill McKibhcn ptrts it,
INTRODUCTION
'nature films are like the highlight clips they show on the evening
sportscasts, all rim-bending slam dunks and home runs and knee-
crumpling knockout punches.'As for diversity, there are about 1.4
million known species on earth. Only a minuscule fraction of these pass
television's audience-appeal standards.
The serious student of ethology must be prepared to observe inactive animals for
many uncomfortable hours under adverse conditions, when even the most avid
ethologist would admit to dreariness and physical misery. Ethology has oftenbeen
glamorized, but it is not always glamorous (See Lott's, 1975,'Protestations of a field
person'). Even determining exactly what it is you want to study can sometimes be
tedious, but this initial step is exceedingly important in the overall process. You can
first define your research interests within the levels of behavior, areas of study and
categories of questions, discussed below.
t.3.t Levels of behavior
Behavior occurs at various organizational levels along the individual-species and
macro-micro dimensions (Figure l.l), a perspective which the ethologist must
obtain and maintain (Menzel 1969). Figure 1.2 gives an example of how these levels
can be viewed for Canada geese (Branta canadensis). Another example of levels of
behavior, using the tvkey (Meleagris gallopavo), is provided in Lehner (1987). The
concept of levels of organization is important to ethologists, and they should be
able to'zoom in'and'zoom out'(Menzel 1969) to and from the aspect of behavior
they are studying (Figure 6.2). We can approach a real understanding of behavior
only if we maintain an accurate overview. Crews (1977) illustrated this point in his
study of the reproductive behavior of the American chameleon (Anolis carolinensis)
(Figure 1.3).
Ethologists must decide at what level they will be conducting research and how
their study will integrate with what is already known at the other levels. This book
will concentrate on methods applicable to the study of whole organisms at the indi-
vidual or group level under fleld conditions.
t.3.2 Areas of study
Many ethologists (e.g. Shettleworth 1983) subscribe to Tinbergen's ( 1963) catego-
rization of four areas of study in ethology:../unt'titn, cuusutiotl, ontog(n.1,, and cyrrlr-
tion.
' ftutt'!itn This ctn inclutlc thc sludy ol'proxirnrtc untl/or ultinrttc lirnc-
lion. rlr whut llintlc ( 1975) hnr cullctl lhc'wcnk rncunirrg'rrrrrl 'llrorrg
WHAT TO STUDY?
LEVELS
Species
Population
CANADA GEESE
Irg l2
FamiryGrouprss-
Dyad W @ asontstc
.J*N*n,..,, ",,,,,,]f,f,* encounter
ffiff,l","
tndividual _f watktng to food
#/ Patch
,*)L,,
BehavioralType €s)1 leedlng
BehavioralAct "'-JJr'''Y' Bl1lg"n'*
Body Parts L bs
Muscles d gastrocnemius
It
Neurons #/-+ tlblal nerve
Levels of behavior in Canada geese. At the upper levels there can be interspecific
and intraspecific interactions with other groups and individuals (drawing by Lori
Miyasato).
sense'ol lunction, respectively. The proximate function refers to the
immcdiate consequence of the behavior on that animal, other animals, or
ihc cnvironmcnt. Through many observations correlations can be estab-
lishctl which lcatl trl conclusions ol cause and effect (i.e. proximate func-
tiorr). Thc ultirnltc lirnction rcl'crs to adaptive significance of the
bchuvior in lcrnrs ol'inrproving thc individual's litness. and how natural
nclceliotr (!l',cnllc$ to rntintuin Ihc hchuvior.
INTRODUCTION
Levels of
Anolysis
specles
orgonismol
peripherol
slruclures
physiologicol
WHAT TO STUDY?
' Causation- What are the mechanisms that underly the behavior? What
are the contexts in which it occurs, and what are the external (exogenous)
and internal (endogenous) stimuli that elicit the behavior? (See Figure
2.2)
' Ontogeny - How does the behavior develop in the individual? What matu-
rational and learning processes are important in the development of the
behavior?
' Evolution - How did the behavior develop in the species? This includes a
phylogenetic comparative approach in which the behavior is studied in
closely related species to reveal differences which may reflect evolutionary
change (Lorenz, l95l ; Kessel, 1955). This often leads to the development
of an 'ethocline'which presents the differences in behavior among several
species along an evolutionary continuum (Evans, 1957). Harvey and
Pagel ( I 99 I ) provide an excellent overview of the new rigor which has
been brought to comparative studies of behavior in an evolutionary
context by the development and refinement of molecular techniques.
They describe several comparative methods to test different models of the
evolution of behavioral traits.
'finbergen's four areas of study can be grouped into two sets which address ques-
Irorrs of 'proximal'or'ultimate'causation (Wilson, 1975), or as Alcock (1989)
rlirlcd, questions o['how'or'why', respectively. The Table l.l below illustrates
It'vcls ol study at which research on the two sets of questions is often directed, as
s'el I as how the two sets can be divided into the study of causes and origins.
ln addition, Marler and Hamilton (1966) suggested the following five broad
,rrcus ol investigation of animal behavior that overlap those of Tinbergen: motiva-
lr()rr. ccology social communication, phylogeny and ontogeny.
I rg I .l Levels of research on Anolis carolinensis reproductive behaviour. At the species
level, pure populations of A. brevirostni (polulation B) exhibit clinical variation
in dewlap color, whereas populations to the north and south, which are sympatic
wilh A. litticltus. have unilorm dewlap colors. At the organismal level, aggresive
posturing bctwcen male A. rurolinensr.r (on the top branch) involves erected
nuchul und dorsal crcst, lateral compression of body black spot behind eye,
cngorgctl throlt, lnd latcral orientation, whereas during the courtship display
(bottom hrnnch), thc nralc has a rclaxed body posture and extended dewlap, and
lhc crcst unrl cyc spot urc abscnt. Thc physiological lcvcl shows some of the
prineipul intrinrie untl cxtrinsic lirctors rncdiutirrg rcproductivc cvcnts in
vcrlchrulcr unrl thcir l'ccdbnck rclntionnhipn. (Atluptctl l'ronr ('rcws. 1977).
INTRODUCTION
Table l. l. The relationships of Tinbergen's four areas of study to questions of
' proximal' and' ultimate' causation
(Wilson, 1975) (Wilson, 1975)
Type of question:
Research directed at:
Origins of the behavior:
Causes of the behavior:
'How questions'
(Alcock, 1989)
Level of individual
Ontogeny
Control (causation)
t33 Categories of questions
Behavior is what an animal does. However, ethologists do not restrict themselves to
examining only what an animal does. Nielsen (1958) stated that ethology also
includes the study of when, how and why, and I would add the study of where and
who.
' What - Adescription of the behavior of the animal.
' Who - Behavior may differ within and between species, sexes, age groups,
dominance ranks and individuals. It is often important to know who per-
forms a behavior, who is present, to whom behavior is directed, etc. The
refinement of DNA fingerprinting techniques has allowed researchers to
determine the genetic relatedness of individuals, such as in the paternity
of nestling house martins (R1ley et al., 1995), red-winged blackbirds
(Westneat 1995) and dunnocks (Prunella modularrs) (Burke et al.,1989),
and of black vultures roosting in aggregations (Parker et al.,1995). It is
extremely important to know the genetic relatedness (kinship) of individ-
uals involved in altruistic behavior (e.g. givers and receivers of care and'
alarm calls). An excellent overview of DNA fingerprinting molecular
techniques and their application in determining kinship is provided by
Avise (1994).
' When-The temporal component of the behavior. This can include the
occurrence of the behavior with respect to the animal's lifletimc, thc
season, time o[ day, or positit.rn in a sc'qucncc. Thc duration ol'a hchavior
and its contribution to an anirnal's tinrc buclgct arc also considcrcrl utttlcr
thc stucly ol' u'/rca.
, Wht,t't' l'his is thc sputiuluspccl ol'u hcltuviot'. Slutlics ittelutlc wltctc tt
'Why questions'
(Alcock, 1989)
Level of individual or
population
Phylogeny (evolution)
Function
WHAT TO STUDY?
behavior occurs geographically or relative to other animals or environ-
mental parameters. Keep in mind that spatial characteristics are three
dimensional.
' How -This includes the motor patterns used to accomplish a goal-ori-
ented behavior (e.g. flying from one tree to another)as well as the under-
lying physiological mechanisms (an aspect not covered in this book).
Studies of the relevant stimuli associated with behavior are included in
this category. The evolutionary and phylogenetic determinants of behav-
ior are also studied to answer ftow questions. For example: How did flight
evolve in birds?
' Why -Two basic concepts underlie the study of the why o[ behavior.
These are motivation and ecological adaptation. These separate, but
related, concepts are generally treated in different disciplines: motivation
in psychology and ecological adaptation in behavioral ecology. However,
the latter is sometimes incorporated into ethological studies, and the
former has figured prominently in conceptual behavior models (e.g. dis-
placement behavior).
The focus of research designed to answer a w&y question depends on
the emphasis the researcher puts on different parts of the question.
McFarland (1985) illlustrated this with the question: Why do birds sit on
eoos?
Why do birds sit on eggs?
Why do birds sil on eggs?
Why do birds sit on eggs?
lVhy do birds sit on eggs?
The different emphases all relate to the adaptiveness of the behavior, but
the focus o[ the research is different (see McFarland, 1985:l-3 for further
discussion).
l'lrc rry'ral question is the starting point for all research; that is, we must determine
nlrirl thc animal does belore we can address any of the other questions. The who
rlreslion is often addressed next, i[ we can determine sex, age, etc. The spatial and
lr'rrf)orirl irspects (tvhcrc aru) uy'rcr questions) are usually relatively easy to measure
,ur(l rrrc lddrcsscd next. Thc ftr.,r, is more difficult to answer, and why questions are
I lrt' rrrost dillicult.
l ltc discussion above should give you a general idea of the various aspects of
,rnrrrurl hchnviol that you might study. The lollowing sections provide an initial
',utlntL.ol'thc stcps iul cth()l()glist takcs in studying animal behavior.
INTRODUCTION
Perceive that a qu6tion exist3
I
Y
Formulate a hypothesis, ot tentative answer
lo the question
(al Oata fail to (b) Dara conf irm
supPort hypoth.sis
hypothesis
I
I
I
5 Use conf irmed hypothesis as basis lor formulating
theory lo coordinate these data into a cohesive
stalement of PrinciPle
Fig. 1.4 Flow diagram of scientific inquiry (from Jessop 1970). Serendipity (fortuitous
discovery) can operate at all stages ol the process.
I.4 SCIENTI}.'IC METHOD
Ethology is a science (McFarland, 1976), and as such, serious studies should adhere
to established guidelines. The 'orthodox biological methods'mentioned in Lorenz's
definition of ethology include the scientific method. The scientific method (Figure
1.4) is a logical, stepwise approach to research in all sciences including ethology
(Tinbergen, 1963; however,seeBaueq lgg2andHailman, 1975,1977 forotherview-
points). This book is organized around the scientific method adapted for use in
ethology (see section 1.5).
Now that I have focused in on the mechanistic approach that will serve as the
foundation for this book, let me state that this does not exclude the pleasure. cxcitc-
ment and artistry inherent in ethological studies. I also want to chanrpion thc
researchers who get to 'know'and cnrpathizc with thcir anintitls. atrtl wlto rccogltizc
and appreciate tlrc hurrnony thut hls cvrrlvc(l bctwccn tlrc itttitttitls bcirtg stutlictl irrttl
t lrc cnvironnrctr I . Scvcttl rcscit rcltct's ltrtvc tlcsclihctl t lrcir st rrtc ol' rttitttl it tttl t ltorrgltt
I
I
3 Determine best means of test ng hypothes sc.9
o
tr
Boc
o
o.;
o
o
oo!
F
o
o!oo
IE
4 Coll
ETHOLOGICAL APPROACH
l)rocesses,.,,hile studying animals in their natural habitat. I would especially recom-
nrcnd readr,lg Tinbergen ( 1958), Schaller ( 1973) and the compilation of autobiogra-
plries by Dewsbury (1985). Dethier (1962) also gives an illustrative and entertaining
tlcscription of the development of his laboratory research on blowflies. Ethologists
.lrould be more than collectors and analyzers of data; they should seek to 'under-
rt rr nd' their animal subjects at a level higher than quantitative analysis can provide.
When we watch animals at different levels on the evolutionary scale,
as when Seitz watches fishes, when Dr. Tinbergen watches gulls, when
Dr. Lorenz watches ducks, when Dr. Schneirla watches ants, or when I
watch doves, the observer can get a feeling ol what is going to happen
next, which is compounded in different degrees ol the intellectual
experience of relationships that are involved on the one hand, and, on
the other hand, of building yourself into the situation. ILehrman, ]9551
I)arling (1937) believed that in order to gain insight into behavior, the observer
rnrrsl become'intimate'with the animals under observation. Lorenz (1960b) sug-
1,t'stod that an even higher level ol empathy with the animals under study is neces-
',,r r y lbr a true understanding of their behavior.
It takes a very long period of observing to become really familiar with
an animal and to attain a deeper understanding of its behaviour; and
without the love for the animal itself, no observer, however patient,
could ever look at it long enough to make valuable observations on its
behaviour. I Loren;, 1 960a: xii ]
l hc ethologists quoted above were not encouraging rampant anthropomor-
I 'lrrsrn (see Chapter 4; at the expense of objectivity (Carthy, 1966). Rather, they were
,,r,rting that genuine interest in the animalper se will foster additional insight into its
I't'llrvior beyond mechanistic (machine or machine-like) data collection and analy-
',n llltirnately, valid research is conducted only by ethologists who have found a
I'rol)cr balance between empathy and objectivity.
r 5 Fl'IHOLOGICAL APPROACH
Irthology . . . is characterized by an observable phenomenon (behavior,
()r' nl()vcurcnt). and by a type of approach, a method of study (the
hiologicirl nrcthod). . . . The biological method is characterized by the
g,cnclirl scicrrt ilic rrctlrocl. ITinbergen, 1963 41 I J
l hc ctlrokrgicirl irpploirch ( lrigurc 1.5) is thc rcsult of titting the scientific method
rl r,111.;l,r*r. ll c()nsisls ol'ir cirlclirl stcpwisc procctlurc by which clata are gathered
,lr(l lulltly/c(l rrrirrg tlcscriptivc strrtislics (tlcscriptivc rcscitrch) or tcst statistics in
INTRODUCTION
Levels
A
Chaptors
(1,2,51
(3)
PERCEIVE A OUESTION
I
CHOICE OF SUBJECTS
at
lrJ
2
F()
UJ-@
o
=UJz
ul
4
lt
llJ
o
Io
G
U
tn
UJ
lr
=uJz
rUF
F
2
(4,s)
(2,6\
(8.9,10)
(11,12-17)
INTERPRETATION H (18)
Fig. 1.5 The ethological approach. The numbers in parentheses indicate the chapters in
this book which discuss the respective steps in the ethological approach'
order to test hypotheses (exPerimental research). The ethological approach expands
on the four basic operations described by Delgado and Delgado (1962): L the isola-
tion of objects or variables to be measured; 2. the establishment and definition of
units of measurement; 3. the comparison of actual events and units; and 4. the
interpretatlon of the meaning ol the observed events.
Even during descriptive rescarch and thc citrlicst stagcs ol'cxPcrimcntal rcscarch
(i.e. rccrlnnaisslncc obscrvitiion). thc cthrllogicul lrpprottch gcttcrltlly inclutlcs ill-
tlclincd hypothcsis tcsting. Whcn wc lirut hcgitt ohscrvirtB utt ltttittlltl. lhc lire t thul wc
UJ
N
A-.n<quJi
q=
=o
DESIGN RESEARCH
r\
EXPERIMENTAL
MANIPULATION
NATURALISTIC
OBSERVATION
DATA COLLECTION
DESCRIPTIVE VERSUS EXPER IM ENTAL RESEARCH
rrre surprised by an unexpected behavior reveals that we had an ill-defined hypothe-
sis about the animal's behavioral repertoire. Most people's approach to life is
through constant hypothesis testing. For example, the very first time we go to work
wc travel a speciflc route which we hypothesize will get us there. After a series of suc-
ecssful trips our hypothesis that our office is located in Room 300 in the building at
llrc corner of Oak and Center Streets gains considerablesupport. However, should
,,ur boss move our office to another building while we are on vacation we will have
I o reject our hypothesis and either revise it or formulate a new one.
More particularly, ethologists often perceive questions which arise from the
rt'ycction of our long-standing theories about the way animals should behave.
. . . biologists are drawn to study events that seem to contradict what we
have been taught to expect on the basis of our knowledge of non-living
things. It is this discrepancy between what an animal 'ought to do'and
what it is actually seen to do that makes us wonder. Like a stone
released in mid-air, a bird ought to fall; yet it flies away.
[Tinbergen,1972:20J
I'hat is, we constantly seek the order which we believe exists in the universe
(t lrrros theorists notwithstanding), and when events occur which seem to upset our
; 
rr econceived ideas of the ways things should be, we either ignore the situation or as
,,t rcrrtists seek explanations through study.
I 6 DESCRIPTIVE VERSUS EXPERIMENTAL RESEARCH
I lre sc two types of research will be discussed in more detail in Chapter 6; however,
,rt tlrrs point I want to stress the importance of both approaches (Figure 1.4). In the
I r r sl ctl i t ion of this book they were designated as naturalistic observation and exper-
rrnt'ntirl manipulation following a traditional distinction (e.g. Schneirla, 1950;
\rt'vcr', 1968) which reflected a field versus laboratory dichotomy. Both descriptive
'ur(l cxpcrimental studies are conducted all along the continuum that connects the
l,rl)olilt()ry and fielcl ( Figure l. I ; Chapter 7).
l)cscription and experimentation become connected out of curiosity and
rrt'tessily. I)cscriptive research olten generates hypotheses which lead to experi-
rrrr'rrlirl rcscarch (Bakcman and Gottman, 1986), and experimental research is pre-
r r'rletl hy cornplctc dcscriptions and definitions of what an animal does
lrlt'rt't'iplivc rcsclrch), Thc lirllowing excerpts from Tinbergen illustrate how his
,,lttrly ol'thc hcgging hchlvior ol'hcrring gull chicks evolved from descriptive to
" 
\ IcIittlcnllrl lcncitlch.
Wlrcrr llrc clticks irt'c ir l'cw hours oltl thcy hcgin to crawl ahout uncler the
l)nlcnl, crtttsing it lo shil'l rrttrl utl,irrsl cvcry so ollcn. Sonrctirncs thc
t4 INTRODUCTION
parent stands up and looks down into the nest, and then we may see
itre first begging behaviour of the young. They do not lose time in
contemplating or studying the parent, whose head they see for the first
time, but begin to peck at its bill-tip right away, with repeated' quick'
and relatively well-aimed darts of their tiny bills' Their remarkable
'know-how,'notdependentonexperienceofanykindneverfailsto
impress one as an instance of the adaptedness of an inborn response' It
seems so trivial and common at first sight, but the longer one watches it
themoreremarkableitappearstobe....Thereactionisinnate,anditis
obviously released by very special stimuli which the parent bird alone
.un p.orid., and which enable the chick to distinguish the parent's bill-
tip from anything else it may encounter in its world'
. . . In the literature we had found some observations which seemed
to show that here again was a reaction dependent on only very few 'sign
stimuli.' . . . Heinroth . ' . wrote (1928) that his Herring Gull chicks had
the habit of pecking at all red objects, especially when they were kept
low, so that they could peck downwards' ' ' ' The special sensitivity to
red was further demonstrated by the fact that Goethe could elicit
responses by red objects of various kinds, and of an appearance that
was rather different from a Herring Gull,s bill: such as cherries, and
the red soles of bathing shoes!
Itseemedtousworthwhiletogointothisproblemalittledeeper.
Thatthechickswererespondingtotheredpatchwasobvious;however,
asthebillwithoutreddidalsoelicitsomeresponse,theremustbemore
in a parent bird's bill that stimulated the chick' Also, the downward
tendencyhadtobeexplained.Asregardsopportunityforexperimental
work, the reactions to cherries and bathing shoes showed that it should
be easy to design dummies capable of eliciting responses' Further' the
veryfactthatreactionstocrudedummieswerenotrare'showedthatthe
chick's sensory world must be very different from ours, for we would
never expect a bathing shoe to regurgitate food'
Therefore, when in the summer of 1946 no war conditions prevented
us any longer from working in the field, I took my zoology students out
for a iortnight,s work in one of the Herring Gull colonies on the Dutch
Frisian Isles. we carried with us an odd collection of Herring Gull
dummies and thus started a study which was to occuPy and fascinate us
during four consecutive seasons. ITinbergen, 1960h' 1 78' 1 84 186 ]
DESCRIPTIVE VERSUS EXPERIMENTAL RESEARCH
thought to be naturalistic studies in the field, and the psychologists'purview was
hclieved to be experimentation in the laboratory.
The physiological approach to animal behavior has become more prominent
ovcr the last few decades, especially with the merging of neurobiology and ethol-
r)gy into neuroethology (Camhi, 1984; Guthrie, 1987; Hoyle, 1984).
Ncuroethology techniques are not discussed in this book, but an introductory
,,vcrview can be found in Camhi (1984) and Ewert (1980). Examples of neu-
rocthology can be found in the synopses of the neural bases of bird song
(Kolata, 1985; Konishi, 1989; Nottebohm, 1989), barn owls capturing mice
(Ktrnishi etal., 1988),batscapturingmice(Suga, 1990),andtoadscapturingflies
{l'.wert, 1987). Neuroethology is an example of one fleld which provides ample
r 'grportunity for cross-fertilization between levels of study within ethology
(l igure 1.2).
It is not only that behavioural analysis can lead to analysis of neural
events, but also that neurobiology should become fruitful in suggesting
directions for behavioural studies. I Bateson, I 987 : j0 I -302 ]
,\ ll irreas, sub-disciplines and levels of study within ethology are important to a full
r n rt lcrstanding of animal behavior.
l he astute researcher oscillates between refined descriptive research and experi-
rrrt'rrtation, using skilled observation in both, better to define and test his hypothe-
',,',, l,orenz expressed his suspicion that experimental psychologists were being
l,rrrtlcd solely by remotely recorded data without observing the behavior of animals
I'l,rt ctl in operant-conditioning chambers.
I can never help a shrewd suspicion that the worshipper of
quantification and despiser of perception may occasionally be misled
into thinking that two goats plus four oxen are equal to six horses.
Counting pecks of pigeons in Skinner Boxes without observing what
the birds inside really do, might occasionally add up to just this.
ILorenz,1960a'72]
I ,,rr'n,,'s comment somewhat overstated the case, but is probably still valid in many
r r',t,rrccs today. 1'he 'balance between the two' (description and experimentation) is
tlrr' le y to good ethological research. However, my purpose here is not to campaign
l,,r 11r,,''. tlircct obscrvirtion in the experimental psychologists'methods (Hutt and
Ilrrtt, l()70.havccll'cctivclydonethis),butrathertoinsistthatethologistsrecognize
tlrr' rnlx)rtiulcc ol'hotlr tlcscriptivc and experimental research, both of which rely
"r 
r ( )lrscrvitl i()tt ltttl t;ulntilicittion.
lrr l()6.1, whilc tliscrrssing thc history ol'cthology. Tinbcrgcn expressed concern
rlr,rt llrt lrulrrrrccwrrsshil'tingloolirrlowru'tlscxgrclintcntatiort.
l5
l'-
l6 INTRODUCTION
We must hope that the descriptive phase is not going to com€ to a
premature ending. Already there are signs that we are moving into an
analytical phase in which the ratio between experimental analysis and
description is rapidly increasing. [Tinbergen, 1963:412]
As we approach the twenty-first c€ntury a further caution is relevant. Theories
and models should not greatly outdistance descriptive and experimental research.
One theory and one predictivemodel each beg for a multitude of experimental
studies which test their validity.
Ethology and its allied disciplines are now racing forward in high gear.
Experimentation and quantification are no longer the tools limited to psychologists
and observation the only tool of ethologists The disciplines have long since over-
lapped, merged, borrowed from other disciplines, and fractured into subdisciplines
There is no longer a territorial battle claiming that methodologies belong solely to
one discipline or the other (Hutt and Hutt, 1970; Willems and Raush, 1969).
Ethologists and psychologists no longer work in their private vacuum$ but rather
they are united with strong subdisciplines in the quest for knowledge about behav-
ior. See Burghardt (1973) for an extensive account of the development of ethologi-
cal and psychological concepts and methods into a more holistic approach.
t Getting started
2 A conceptual model of
animal behavior
I lrc model for a behavioral act I develop and discuss below is an extension of the
rrrodel I presented in the first edition of this book. I have found the model to be
sirnple enough to be a useful research tool, yet complex enough to accomodate most
Irchaviors and environmental contexts. It has assisted students of animal behavior
rrr studying, understanding and explaining what an animal is doing now, as well as in
prcdicting what it will do in the future.
The model will not meet with universal approval amongst those who forage
t lr rough this book. However, the model is not presented as a 'general law of behav-
r,rr'' nor is it designed to quell or exacerbate controversy. The purpose of the model is
Itt;
t Provide a framework on which to design and conduct ethological
research, and
z Assist researchers in putting areas of study and types of question into an
overall perspective while at the same time focusing on their specific
research objective.
I lrose readers who do not agree with the assumptions I make in building and apply-
rrrg the model are encouraged to make their own modifications. To that end, I
rlrscuss each portion of the model in sulficient detail to explain how the model
rvorks and to allow each researcher to modify and expand those portions which are
rrrrrst important to their study (see section 2.4.4). Also, one should examine other
rrrotlcls with varying degrees of similarity that have been offered by several etholo-
I'rsts (e.g. Hinde, 1982; Lorenz, l98l).
] I CONTINUOUS STREAM OF BEHAVIOR
Anintals arc always behaving. They perform a continuous stream of behavior from
llrc rrrorncnt whcn movcment can first be detected in the embryo until their death.
It is inrpossihlc (at lcast irnpractical and inefficient) to study all of an animal's
lrelrirvirlr throughoul its lilbtinrc. Ilowcvcr, sincc an animal's behavior is not
rrrttrlottt. thc rclutivc li'cqucncy und tlurulion ol' tlill'crcnt hchnviors can hc approxi-
A CONCEPTUAL MODEL OF BEHAVIOR
mated through sampling. Normally, our sample is a continuous, but restricted,
segment (or segments) of the stream of behavior, or a series of samples at points in
time (see section 8.3). The behavior being perlormed by an animal at any point in
time can be considered a behavioral act (see Chapter 6). The modeldeveloped below
is for a point in time (behavioral act), but a series of models can be strung together
to analyze a segment of the continuous stream of behavior.
2.2 PREDISPOSITION TO BEHAVE: DIFFERIn-G
CO NT R I BUT IONS
An animal's predisposition to behave (i.e. probability of rcsponding to specific
stimuli with specific behaviors) is the result of a combination ol' factors expressed
below.
Behavioral predisposition:(Gu* EB+ I )+ (AB+PB)
Where: Gu:contribution of the genotype. primarily.
Eo : contribution of the environment (including experience), primarily.
1u:contribution from the interuction of the genotype and Environment.
lu:behavioral capacity provided by the animal's uttcttomy.
Po:behavioral propensity and capacity provided by the animal's physiolog-
ic'ulmechanisms.
Using a computer analogy, (GB+E'B+18) can be thought of as creating, modifly-
ing, and containing the so.fix'are that consists of 'closed' and 'open' programs
(Mayr, 1974). Closed programs are primarily a result of the genotrpe and do not
allow appreciable modification; open programs allow for modification as a result of
environmenlal input that provides experienre. The (AB+P) is the hurclv'are which
stores the programs (e.g. brain) and provides the machinery for their action (e.g.
sensory, nervous and muscular systems).
z.z.t Genotype, environment (experience) and interaction
The (G'+EB+18) portion of the predisposition to hehave modelis thc sarnc us thc
formula used by population geneticists (e.g. Futuyama, 1986) to exprcss thc total
phenotypic variation in a population (V,) as the sum of thc vuriatiort tlrrc lo geno-
type ( 2,,), environment ( Zn), and the interaction ( [',) ol'gcnotype irntlcrrvirrrrrrrcnt:
Vr:V,+Vt+l/l
Altttost ltllctltolopists(e.1'. l|;tlcsott. l()tl);uttl Psytltolol,isls(r'.,'. llttlrl', l()S.)llutvt'
t'ottt'lttrlt'rl lllrl ;ur ;urnr;rl's lrr'lrrt r()r r', llrt' tr':ttll ol lrollr rl', y'r.'11,r1\ |t' ;rrrtl llrt't'rrvr
PREDISPOSITION TO BEHAVE
rr tt)I11eflt, as well as their interaction (see below). There is no direct correspondence
l't'lween a gene and an individual behavior pattern (Bateson, 1987), and the interac-
rr()rr of the genotype and environment is likely to be so complex that it is very diffi-
, rtlt to identify the genetic and environmental components of an individual
l','ltltvior (Bateson, 1983), or the extent of their contribution. For example, Lyons 4r
,/ ( 1988: 1323), in their study of the development of temperament in dairy goats,
,,;tclled only the general conclusion that An individual's genotype and its early
1',rsttlatitl environment both contributed to processes underlying the development
I stable individualdifferences in temperament [timidity] . . .,.
Nevertheless, it is still heuristic to make some generalizations aboutthe relative
' "rttribution of the genotype and the environment as functions of both phylogeny
,rrrtl ttntogeny.
lior those species in which the environment (experience) plays a relatively large
" 'lt' in the lif-e history of a species (e.g. birds and mammals), the relative contribu-
rr()rr of genotype and environment is believed to change ontogenetically (Figure
t)
l:arly in life, in addition to the effect of it's prenatal experience, an animal's pre-
' I r ,l)()sition to respond to 'releasers' and 'unconditioned stimuli' (see section 2.3.5a)
, I'ritnarily genetically determined. Also, as the animal matures its predisposition
r" l('itl'n more readily in response to certain stimuli and reinforcers may be geneti-
' , r ll', controlled; this has been called 'preparedness' (Seligman, 1970).
).2.ta Genotype
\rr :tliom at the roots of ethology is that there is a genetic basis lor variation in
r" lr,t'n'ior between individuals (e.g. Partridge. 1983). The entire field of behavioral
"' rr\'{ics is based on this axiom. Behaviors that result from genetically fixed, closed
l,r,'r'r'lrns are called innate (e.g.egg laying in a snail, Scheller and Axel, lgga);
lr"rteVCl'. the environment provides lor the proper development and expression of
r 1,, ,rs' i11n31e behaViorS.
\rtyone familiar with breeds of dogs selectively bred for various tasks, such as
r' tr teviltg game and hercling livestock, recognizes that an animal's genotype con-
trrlrttlcs to its bcltavior. It is also evident that to realize its full potential, that pre-
'lr,lrositiotr to rctt'icvc or lterd must be shaped in the proper environment. The
" ttt)/t'1,('itlso Provitlcs thc bltrcprint for the development of the onutomy and phys-
,i,,.ti1,.
( it'ttt's ('()tlttil)tltc to tlte obsct'vctl tlilll'r'cnccs bctween inclividuals.
lil,lll:l' l,:; "j)':,1 ;';,i'1,:lll:::.i lll'll, lllll,l:lili,::l:l',i':j'::llilll;',,,
Iltr' t trttlt tlrrtltr)t) III)nt Ilt(. (.nVil()ilnt('nl (.;tn f l),ttlrtrt. l(),\(t \ i I
A CONCEPTUAL MODEL OF BEHAVIOR PREDISPOSITION TO BEHAVE
type and environment interact. Gould and Marler (1987) referred to'innately
guided learning'. This interaction is reflected in: 1. Hailman's (1969) title, 'How an
instinct is learned', for the report on his study of food begging in laughing gull
clricks; and 2. Ewert's (1987:331) conclusion that prey-catching in toads is 'medi-
ltcd by innate releasing mechanisms (IRMs) with recognition properties partly
rrrodifiable by experience'.
Also, the genotype, along with the animal's anatomy and physiology place'bio-
Itrgical constraints on learning' (e.g. Hinde and Stevenson-Hinde, 19"73;
Slrettleworth.1972). That is, '. . . learning, rather than occurring indiscriminately, is
'rrhject to species-specific and task-specific limitations and predispositions'(Roper,
l()ll3:185). The classic example is Garcia and Koelling's (1966) demonstration that
rrrts readily associate taste (internal cue) with illness and exteroceptive cues
rlrsht/sound) with painful electric shock, but they don't readily associate taste with
,lrock or light/sound with illness.
In summary, behavior that is initially programmed in the genome can be devel-
,,1rcd and expressed only in the proper environment and can be modified by experi-
, ncc (learning) only within constaints provided by the genotype, environment,
. r rrrtomy and physiology.
2.2.2 Anatomy and physiology
\ rrrloffi! and Physiology both enable and constrain behaviors. Wings (along with
' , t lrcr adaptations) allow a bat to fly, just as the lack of wings contribute to a mouse's
rrr,rlrility to fly. From the earlier analogy, an animal's anatomy and physiology is the
i,,rr,ltrut'c necessary to perform behavior and store feedback from the environment
r r('nr()r'y), allowing for modification of future behavior. Anatomy (including mor-
I 
,lr,,logyl and physiology develop according to a genetic blueprint, but that develop-
l,r('n l is rrll'ected by the environment. For example, Zeki (1993218-219) summarized
rl,,' results ol'Hubel and Wiesel's extensive research in the 1960s and 1970s on the
, tl,'t l ol'scnsory deprivation on the development of the visual system of cats and
rrr, rn kcyS hy stuting: 'at the cellular level, there is a critical period, during which ade-
,1rr,rlr' vrsrnl stinrulation is mandatory if the animal is to be able to see at all, even if
r, , ,rll ;rpl'rciu'iurces thc visual pathways and cortex appeared to be intact'.
Itt'st';rrclrcrs lrrrvc rtlcntilicd thc brain centers and neural pathways necessary for
rlr,'tlt'r't'loprrrcnl. nrcn)()r'y lrttrl pcrlirt'rnunce of bird song (e.g. Nottebohm, 1989).
I lr.' lrr;rin ('('nt('r's lirr birtl song tlcvclopmcnt arise in part from a genetic blueprint
,rr(l ur l);ul lrorn t'rrtltil'('n()us lrrrrl cxtlgctttlrrs stit-t-tttlatit.ln. The hormones (endoge-
r, ,u'. 'rlrnrrrlr) n('(('\sirrV lirr slirttulrrtinp', tlcvclrll'llncttl itrc thcmselves triggered by
, .('1,('n()lt\ \lrnrrrlr (('I l)lr()lo;lr'rrrltl rrtttl lt'ril1lt't':tlttt'e ). ltt s0tttc spccics thtlsc brain
,,trlr't., ,|t('lil(|rltltr'rl l,t t'r,]l'('n(]lt\ rltttrrtl;tlr()rl 111 lltt'lirt nt ()l sol)1ts ll'0ttt rllltct'
23
o
"oLr
tro(J
q)
.lJ
cl
6J
&
Oo/o
fre-natal
,"6@8
Individual's lifetime
Fig.2.1 The relative contribution of the genotype and environment during an animal's
lifetime. Variation between species and individuals indicated by dashed lines
(drawing bY Brenda KnaPP)'
2.2.1h Environment and experience
As described above, the environment (biotic and abiotic) provides lor the proper
development and expression of innate behaviors and predispositions. This is also
true lor behaviors that are primarily learned. That is, the environment also provides
experience and the proper context for expression' For example, squirrels have to
learn through experience how to efficiently crack open and eat a hazelnut (Eibl-
Eibesfeldt, 1963); they can develop and later express this behavior only in the pres-
ence of hazelnuts, or similar nuts. Experience results from the various associtttions
of stimuli, behavior and consequences which are the bases for learning and modif y-
ing future behavior (Davey, 1989; also see section 2.3.5). The envirt])nmcnt itlstr
aflects the anatomy and physiology through factors such as injury, cliscitsc. clittiittc.
and nutrition.
2.2.1t' Intcrat'tion o.l' ganotypt' ttttil t'ttlifttttt"t'ttt ( t'tparienu')
wc trttriltrrlr. 'irrrr;rlt" llclr;rVit)ts l)ilnlilltlV to lltt' l't'lttrlylx' iltlrl 
'lt'lttttt'rl
l)illniiltlV lo llrt.r.rrYrr()liln('ltl (t'r1rt'ttt'tttt'). rt't';tl:.,r Ltl()\\'llt;tl lltt'1't'ttrr
Althorrglt
lrt'lutviots
A CONCEPTUAL MODEL OF BEHAVIOR
males of the same species in order to develop the'innate template'into an'acquired
template'.
Therefore, bird song occurs in response to stimulation from the appropriate
neural pathways (physiology), and its form results lrom a genetic blueprint (geno-
type) and learned modifications (experience) stored in the brain centers (anatomy).
For example, the genotype provides the 'innate template' in the young Swamp
sparrow's brain that allows it to filter out all but swamp sparrow syllables from the
songs it hears in the environment (Marler and Peters,l9lT). The adult male swamp
sparrow songs it hears provide the syllables to create the 'acquired template'which
will be the basis for comparison when the young swamp sparrow begins singing its
subsong, listening to itself, and improving it vocal output to create its crystallized
primary song.
2.3 A MODEL FOR A BEHAVIORAL ACT
2.3.t The animal
The basis lor the animalin the model is the formula for it's predisposition to behave
described above. That is, all the important components that predispose an animal to
perform specific behaviors under a given set of environmental conditions are pro-
vided by Gu, EB. IB, A,and P. Also incorporated into the animal portion of the
model are endogenous stimuli (discussed below). Other parts of the model (Figure
2.2) are e-\ogenous stintuli, hehavior, ('onsequen('es, contingencies, feedbac'k and./bed-
forward, all of which are discussed below
2.3.2 Stimuli
Stimuli are changes in the environment (internal or external) to which an animal
normally responds. However, the environmental context in which the stimulus
occurs will determine whether it is effective in eliciting a response. Therefore, an
effective stimulus is a change in the environment which elicits a response at that
point in the animal's stream of behavior when the environmental context (internal
and external) is appropriate. Stimuli that are effective in one context may be filtered
(centrally or peripherally) in another context. For example, cat lirocl kibblcs will
normally stimulate feeding only when the cat is hungry (interrral cttvirot.ttt'tcttt ) itrttl
not involved in a higher priority activity (e.g. chasing a r.nousc extct'ttitl ctlvittrtl-
ment).
Stirrrrrli havc httll't trt'tit'tttirlrrrl ltttrl ttr,qtrtti:ttliorrrrl litttcliotts. 'lltltl is. tltev ttol
only ittitittl,lrrrtl olirll lrr'llrviot'rlit't't'lly, lrtrt lltt'Y ltlso lttr ililrtlt';tnr,l ttt,rittl,ttrr lt.'lt:n'
i0t lttttl ltrt'tlttltrttt';tll ;tllllllill l() l)ilt ltt ttl;tl lrt'll;tVtt,ts
Exogenous
stimuli
\
A MODEL FOR A BEHAVIORAL ACT
Positive feedback
e--"-- 
t't irr
'-?--> Behavior 
\\\r.
-+ Behavior -) 
Consequences '-) Feedforward
, (Contingencies)
-a,,\,'t-a- 
,ttstl-s 
------ -'
Negative feedback
I ig. 2.2 The model for a behavioral act.
2.3.2a Endogenous stimuli
I rttlogenous stimuli arise from the animal's internal environment. An assumption of
rlrc model is that all behavior is the result of exogenous and/or endogenous stimula-
rron. Th&t is, we operationally define behavior as that which an animal does as the
rr'srrlt of stimulation. We observe behavior being emitted, but we assume that all
1,,'lravior is elicited. Like Kuo, the Model assumes that'there is no such thing as
,lrorrtaneous behavior'(behavior thutis not stimulated) (quoted in Marler and
I I;rntilton, 1966:605). However, there are behaviors that occur for which we cannot
,t('rcrmine the source of stimulation, and these are often called'spontaneous'
1,,'lurviors (e.g. Hinde, 1966).
Although behavior does not occur spontaneously, it may be elicited by endoge-
rr.rrs Stirnuli that arise spontaneously.
. . . every cell in the nervous system is not just sitting there waiting to be
told what to do. It's doing it the whole darn time. If there's input to the
nervous system, fine. It will react to it. But the nervous system is
prirnarily a device for generating action spontaneously
IGraham Hoyle quoted in Allport, l986J
L)r ('xiu.nple, Bekoff (1978a) found neural pattern generators in embryonic chicks
rlr.rl slintulatc coordinateci limb movements and develop in the absence of any pat-
I, rnr'(l sct'ri()ry inptrt.
llrcrc rrrc llso bchirviors that occur in the absence of the exogenous stimuli that
r)(,r nrirlly clicit llrcnr (c.g. hirrls'nest building'without materials, cats'prey catching'
'r rtlrorrl grrt'v. tlogs 'btrryirrg' lrttl 'covering' food in a concrete floor). Lorenz
,.,1,1;rrrrt'tl llrt'ot't'rrrrerrr,'c ol'llrcsc'vircrrtrttr'behitviors its an excessive buildup of
r( tr()n spt't'rlrt't'rrt'r;,y'1ullt'lt lirrcctl oPctt (ltc vltlvc itt lris Psychohytlraulic Model;
l ,rrt'1t,,. l()\O) llorvt'r't'r.;tn()llrt'r Possilrilitv is lllrt v:rctrutu bclutvior is clicitctl irntl
,,r rt'nlr'rl 1,1 trrr,rl,nt;u \'('\ol'('n()lr\ slttttttlt't tt';tlt'rl lrv tlrt'ltttitttltl (ttlsrl sttl'llestetl by
(G+E+D+(A+P)
A MODEL FOR A BEHAVIORAL ACTA CONCEPTUAL MODEL OF BEHAVIOR.
Lorenz,l98l); lbr example, we refer to'hallucinogenic'play in cats, implying that
the'prey'is in the cat's'mind's eye'.
Physiological needs are signaled through endogenous stimuli that elicit behav-
iors designed to meet those needs. For example, low blood sugar leads to the 'state
of hunger'which stimulates the anirnal to seek, find and ingest food.
There also appears to be a psychological need to perform a normal range of
behaviors. Various terms have been applied to this psychological need, including
'ethological need' (Hughes and Duncan, 1988), 'drive' and 'instinct'. For example,
Garcia et al. (1973:3) state that 'drive is the psychological concomitant of physio-
logical need', and Dawkins (1986:64) states that 'instinct . . . refers to the inner drive
or motivational force that leads an animal or person to behave in a certain way'. The
model acknowledges that behaviors can be elicited by endogenous stimuli regard-
less of how you choose to perceive and label the basis for those stimuli.
2.3.2b Exogenous stimuli
Exogenous Stimuli come from the external environment (biotic and abiotic), take
many forms (e.g. light, sound, odor) and arrive via the animal's various sensory
receptors (e.g. eyes, ears, nose). The animal's anatomy and physiology are responsi-
ble lor receiving, processing and responding to exogenous stimuli, as well as gener-
ating behaviors which produce exogenous stimuli. Several terms have been applied
to exogenous stimuli depending on the role they play in different behavioral para-
digms. Sign ,stirttuli, relea,sers, unconditioned ,stimuli, neutral stirnuli, conditioned
stintuli, and disc'riminative stimuli are all discussed in the contexts of the ethological
model of innate behavior and the learning paradigms below.
2.3.3 Behavior
Behavior results when an effective stimulus is received or generated by the animal.
As shown in the model, when one behavior is elicited, an ongoing behavior may be
inhibited. This is required if the the two behaviors are mutually exclusive; that is,
they cannot occur at the same time (e.g. sitting and walking). A behavior may also
stop because it is no longer stimulated. For example. sleepingis inhibitcrl when an
animal is ingesting food; ingestion will cease when the animal is satiated untl cirting
is no longer stimulated by the sight and smell of food.
2.3.4 Ethological model of innatc bchavior
'l'lrcclltolog,tcltl tnotlel ol ittn;tlt'llt'lutviot llrt'lorv. ('.1'. l.ort'nz. l()liI)ist';rsrlv rrrtor
l)()t;rl('(l tnl() lltt'tttorlr'l (l'llrut(' .' l)sttttt'rl rtrrolvt'r t'\,)1,('n()l\ slnnrrlr,;ur:rl()nlv
Releaser(s)
+
Key stimuli
v
Positive feedback
e--tt------isr\ 
i\r
--?-+ Behavior '...
+ Modal action -) 
Consequences -) Feedforward
pattern
F,...- .r't-'----- 
ootat'/-
Negative feedback
,r, 
(Contingencies)
I ig. 2.3 Where the ethologists' model of innate behavior fits into the model lor a
behavioral act.
rrrtl physiology, and behavior. This hypothetical construct is diagrammed as
l, rllttws'
Releaser(s)*key stimuli---innate releasing mechanism (IRM)
J
modal action pattern (MAP)
A morphological structure and/or movement (releaser) emit one or more tey
'rrrttuli. The key stimuli operate on the innate releusing nrcchanism (at present, an
,rrritlcntified part of the animal's anatomy and physiology) which 'releases' a modal
'r, titttt pattern, a relatively stereotyped behavior pattern. Since these modal action
l,.rllcrns are very similar between individuals of the same species, ethologists
1,,'licved that they are primarily under genetic control and originally referred to
rilr'r)r irs .fi.rcd uction potterns. However. it is now recognized that experience also
t,l;rvs un important role. For example, Gerard Baerends, who began his ethological
r,.r'iu'ch six decades ago. recently concluded from his many years of studying
1,, ring gulls that'The infbrmation encoded in the lP.Mlinnate releasing mecha-
,,irrf iulrl the acquired inlormationfleurning]were found to work in combination.'
r rt,rlrcs tninc, I9u5:37).
llistoricirlly, cthologists and psychologists have been branded as having diamet-
rr,;rlly o1-r1-rosctl vicwpoints on the relative contribution of the genotype and learn-
rrrj' lo bclurvior'. llowcvet. cthologists and psychologists are increasingly borrowing
lrr )nr ('ir('l) olltcr''s rcsciu'ch lntl llrcorics. and overlap between ethology and learning
tlrcotv ('rn nr()re relrtlily ltc lirrrrttl in thc litcr:rture. For example, adjunctive behav-
,,,r, r,l lt';ttttttrl, lltr'orrrl\'iu('r't't'y sitttilru'tlvltirtnicirlly irncl tirnctionally to what
l,,rrt'lrt't'lt krrorvrr rrr llrt't'llrolol,it';rl litenrlrrrc lrs tlisPlirccntcnl irclivitios'(Davey,
l't1.'t1 5t1,
Animal
lnnate
releasing
mechanism
A CONCEPTUAL MODEL OF BEHAVIOR
2.3.5 Associative learning paradigms
Learning can be defined as the 'adaptive'modification of behavior as the result of
experience (e.g. Lorenz, 1965). Natural selection has shaped various types of
learning in animals (Staddon, 1983), but each type of learning incurs selective
costs (in terms of fitness), as well as selective benefits (Johnston, 1981). Also, the
benefits of a specific type of learning may be limited to the environmental contexts
in which it evolved (McNamara and Houston, 1980). Possible routes of evolution
of the primary associative learning paradigms, clossic'al and instrumental c'ondi-
tioning, are discussed by Weisman and Dodd (1980) and Skinner (1988), respec-
tively. Both of these learning paradigms are incorporated directly into the model.
2.3.5a Classical conditioning
The classicul conditioning paradigm (below) describes how neutral stimuli become
conditioned through association, thus gaining the ability to elicit specific behaviors.
elicits
UCS .---.------------------.-* UCR
elicits
NS+UCS UCR\\'.. elicitsta,
CS--.--..----.------*CR
An unconditioned stimulus (UCS) elicits an unconditioned response (UCR).
When a neutral stimulus (NS) is paired with the UCS, over time it becomes a condi-
tioned stimulus (CS) capable of, by itself, eliciting a conditioned response (CR), a
reasonable facsimile of the UCR.
Note the similarity between classical conditioning and the ethologists'model of
innate behavior (discussed above). The UCS is essentially the same as the etholo-
gtst's releaser, and the UCR is essentially the ethologists'MAP(FAP).
23.5bInstrumental ( operant ) conditioning
The instrumental conditioning paradigm (below) states that a behuvirtr is emitted ancl
is followed by consequences (So*, So ) that either maintain, increase or decrease the
probability of that behavior occuring again (see Consequences scction bclow).
Discriminative stimuli
15t), ttr SI) )
Ilcltlrvior'
(r'rrriltt'tl)
\/-\trs 
---------t'
Negative feedback
l'ig. 2.4 Where classical and instrumental conditioning fit into the model for a behavioral
act.
The paradigm begins with a behavior being emitted and does not consider
,trrtruli that might elicit that behavior. However, the paradigm does include tliscriru-
rtrtrtit,c stimuli. Figure 2.4 illustrates how both classical and instrumental condition-
rrrs lit into the model.
D is c r iminat i v e s t imu I i
l'( )sitive discriminative stimuli (S"*) predict that a specific behavior will be followed
l,r l.rositive consequences, and Negative discriminative stimuli (So ) predict that a
'Pr'cific behavior will be lollowed by aversive consequences (see discussion below
rlrottt specific types of consequences). Since exogenous stimuli in the model include
l,,,th conditioned and discriminative stimuli as types of exogenous stimuli, it is
rrrtcrcsting to note how Davey summarizes their similarity in function.
. . . Pavlovian CSs or instrumental discriminative stimuli (SDs) elicit a
motivational state appropriate to the reinforcer and . . . this
motivational state in some way mediates the emission of the
instrumental response. IDavey, l9B9:210J
llrt'rrbility to usc thc cnvirc>nmental context (including SDs) to predict the conse-
,lu('nce s ol' bcltrvior is a marjor benefit of learning. Tarpy presents a psychologist's
t','rspcclivc without using the term discriminative stimuli.
l,c:tt'ttittg is I'rrttrlunrcntally a process whereby the animal comes to
crpcel rt lirlrrt'c cvcrtt birscd upon the patterns of stimuli in the
('n\'u()nntt. rrt or rr1'rtlll its own hcltitviol ITurpv, 1982:lB l9J
I tkr'ttlrt'. I r)l('tll l)l('s('ttls lttt r.'lltolollist's ltcrsPective rlrt prctlictirrg tlrc tltttcrllt.tc ol'
l', lr,r\ lot. itl\o rr rllrorrl rrrrrrll lltt'l('lln (lt\( tlnlnt;tltrr.slirnttlt.
UCS/CS or SD
\
A MODEL FOR A BEHAVIORAL ACT
Positive feedback
k-"-
+
--?--> Behavior
+ Behavior
IJCR
Consequences
, (Contingencies)
--) Feedforward
Animal
(G+E+D+(A+P)
( tlnsetlrtcrtt't's
A CONCEPTUAL MODEL OF BEHAVIOR
Table 2.1. During or immediately.follow,ing the behavior the rein/brcing stimulus is:
Reinforcing stimuli Presented Omitted
A MODEL FOR A BEHAVIORAL ACT
domestic chicks, during the process of socializatron, received 'self-reinforcement'
from social experience during the early sensitive period. Positive reinforcing stimuli
that meet these ethological needs are said to have an underlying 'hedonic value'
(Tarpy, 1982); that is, they possess a sub.jective quality of a positive affective state
(Toates, 1988). Whether this is pleasure as we know it, or what Lorenz calls 'feeling
good'and'satisfaction'(Nisbett, 1977:138, 289), does not affect the operant condi-
tioning paradigm or the model. Even reinforcers that meet basic physiological needs
might be considered hedonistic.
I have seen that rats drink more of stuff that tastes good. And I do not
see anything bad in thinking of this hedonistically; they like it, they do
it. [Bolles, |9BS.450J
' Aversive reinforcing stimuli(So ) are stimuli which the animal perceives as
'bad'(e.g. pain). That is, under those conditions the animal will perform
behaviors necessary to avoid those SR s.
' Positive reinforcemenr results when the consequence of performing a
behavior is receipt of SR*. The probability of the behavior occurring
again is maintained or increased.The SR*s which result in positive rein-
forcement are received under different contingenc'ies, discussed below.
' Extinction ( omission ) can only occur after an animal has been positively
reinforced for a behavior. If that same behavior now does not result in the
animal receiving the SR+, omission is the consequence and the probability
of the behavior occurring again deueases until it is extinguished.
Extinction is not simply a dissipation of the response, but is an active
learning process (Davey, 1989).
' Punishmen r results when the consequence of performing a behavior is
receipt of SR . The animal initially escapes the SR , and the probability of
the behavior occurring again decreases.
' Negutive reinfbrcement can only occur after an animal has been punished
lor a behavior. Ii under the same conditions in which the original behav-
ior resulted in punishment, a different behavior results in avoiding the
Sr{ . then the probability of that behavior is maintained or increased.
llrcse lirur proxinrutc consequences probably rarely operate alone, but rather in
',r,nrr cr)r))birrirtion. ['or cxample, Balph ( 1968) found that individual Uinta ground
,(lun rcls (,\1x'rntttpltiltt.t ttrnrtttrr,r) diffbred in the probability their being retrapped
,)n('()r rrrorc lirrtcs. llirsctl ort ltis obscrvations. he concluded that each individual
,tlur rcl rlrlli'rcrrti;rllv we iglrctl tlrc 1'rositivc rcinlirrccrnent of the bait versus the pun-
r',lrrrrt'rrl ol lrt'rrr1'lrrrppr'tl l.rkr'rvisc. lrittirrg yorrr hlrking rlog with a newspaper
(Sl' ) rs rrol lrrrrrrslrrrrt'rrl rrrrlt'ss llrt'lr;rt'kin1, slops. ll'tlre llrrg tturitttirirts ot'ittcrcitscs
rl'. lr.tt lrlilf'. lltr'tt lltt' ttt'r'tttll ntl(',ttt ltt)u t\ Pr'lr'r'ttt'rl lrf' llrt'rl()l'. rts ll,lsitivt' rcirtlilt'ec-
Positive (So*)
Aversive (So*)
. . . a bird that 'wants'to carry out the beautiful motor pattern of nest
building . . . learns to recognize the situation in which performing the
nest-building movements gives the maximum satisfaction.
ILorenz, 1981.291]
Consequences
Proximate consequences The fourproximate ('onsequences, in the matrix shown in
Table 2.1. are the immediate result of a behavior. They are determined by the type of'
reinforcing stimulus and whether the reinforcing stimulus is presented or omitted.
Reinlorcing stimuli and consequences are defined by their effect on the animal's
behavior. Positive reinfrtrcing stimuli (So*) are often called rewards. They are rein-
forcing stimuli which the animal perceives as'good'. That is, in the appropriate con-
texts, the animal will perform the behaviors necessary to receive those SR*s. The
SR*s are received by the animal under different contingencres of behavior called
schedules of reinfbrcement (discussed below).
An SR* may be a single stimulus (e.g. food item) or the opportunity to perform a
chain of behaviors (e.g. search, stalk, capture, kill, consume). Lorenz (1965) consid-
ered the consummatory act in a chain of behaviors as a reinforcer for antecedent
behaviors (appetitive behaviors). Also, behaviors may be organized in a 'preference
hierarchy'(Premack, 1965) so that an SR* could be the opportunity to perform a
preferred behavior.
Although we often think of SR*s as meeting obvious basic physiological needs
(e.g. food and water), ethological needs (discussed earlier) may stimulate an animal
to perform behaviors in order to obtain subjective rewards.
. . . the opportunity to manipulate, to explore, or to merely observe is
labeled a reward, reflecting the assumption that if learning hits ttccurrcd
there must have been some reward, even though it citnttot bc crtrpirically
specified. f (itrr<'itr ct ll . /97i i.i/
Anin-rals nt:ry pcrlrlrrn belrirviors llurl rrt'c pt'irttrtt'ily irttt;rtt' (r'1,, t'otttlsltip lttttl
rrrirtirrg) ltccirrrsc tlrcy tc('('iv('rttlrt'tcttt. sttlrir't'tivr'tt'wttttls. lirr t'x;ttttplt'. irt
Si1'rrrrrnrl's 1lt)t)1..)0i',i ) r'it.rr'. '1ll;rV rs tls ou'n t('\\'intl' (',rlllts (l()(r.)1 tlott'tl llt:tt
Positive reinforcement
Punishment
Extinction
N egative reinforcement
A CONCEPTUAL MODEL OF BEHAVIOR
ment. That is, the dog's interaction with you (SR*) outweighs the aversive aspects of
being hit with the newspaper (SR ).
Reinforcers and reinforc'ementas inJrtrmation Consequences in instrumental con-
ditioning provide not only immediate reinforcement, but also information (e.g.
Cherfas, 1980). Garcia et al. (1913) argued that since natural selection'has favored'
animals that seek and incorporate information, we should think in terms of animals
acquiring information rather than receiving reinforcement.
I prefer to retain the terms positive and negative reinforcement while using the
term 'information' in two contexts: l. as a reinforcing stimulus; and 2. as feedback
about the relationship between stimuli (classical conditioning), and stimuli, behav-
ior and consequences (instrumental conditioning).
First, I agree with Garcia et ttl. (1973) that in/brmation can, by itself, serve as d
reinfrtrcing stimulus. This concurs with Lorenz (1981) who stated that animals are
motivated by curiosity to gather information. For example, an animal might seek
more information about a novel object it sees in its environment by listening,
smelling, tasting and touching it. What it hears, smells, tastes and leels are reinflorc-
ing stimuli for the respective behaviors. The reinforcing stimuli all provide informa-
tion, but they can also be perceived as positive (e.g.smells'good':positive
reinforcement), aversive (e.g. tastes t6rd':puflishment) or neutral (e.g. feels
rough:no consequence (see below); provides only information about its texture).
Secondly, the animal obtains in/brmation via /bedback about the relationship
between the stimuli eliciting the behavior, the behavior, and the consequences
(including information about the object). In all cases the animal is acquiring infor-
mation (via feedback) about information (reinforcing stimuli). In the case where
touching the object results only in learning that it feels rough (neither positive nor
aversive), that information alone is a reinforcing stimulus, and the animal has
obtained information about gathering information. That is, they have learned that
when a novel object appears in their environment they can learn more about it by
touching it. In this context, the use of the term information agrees with Plotkin
(1988), who considers learning to be the acquisition of information, and most cog-
nitive theorists who think of animals as acquiring information about their environ-
ment (Bolles, 1988). Likewise, classical conditioning is seen by many as the
acquisition of information about stimulus relationships (Davey, 1989).
The use of the term information in these contexts in no way negatcs the utility ol'
applying the term reinforcement to conseqLlences in instrurrne ntalcontlitioning.
('ott,tt,tlttt,ttt'c,s ttf tttt t,ttlttt Sontc llclurviors irl)l)elr l() r('sull irr t'orts,.'tlrt'nt'r's llt:rt
It:tvc tto t'cittlirt'cing vrrluc (i.c. tlrev rrrt'sr'r'nrirrl'ly pt'rt'r'ivt'tl ;rs rrt'illrt'r l)()srli\'('n()r
rn'r'tsivt'). ( )ttt' t'rlrtnplt' ts llrc lttrltrtttttltt,tt o l unt ottrltltonr'.1 (llr nn;rttl\' ttttr;rlt')
A MODEL FOR A BEHAVIORAL ACT
behaviors such as the predisposition to show fear/avoidance of novel stimuli. The
response wanes and disappears (habituates) if it is neither immediately inhibited by
punishment nor maintained by positive reinlorcement.
Satiation of a drive such as hunger can also be perceived in a similar manner.
Initially, the consequence of ingestion is positively reinlorcing stimulation (SR*);
Itowever, the reinforcing value decreases until satiation is reached; at this point its
rcinforcing value can be considered zero (neither positive nor aversive) and the
behavior would normally cease. Should the animal continue to ingest, the food
would begin to become aversive (S* ) and punishment would be the consequence of
lirrther ingestion; hence the behavior would cease.
(lltimate Consequences Proximate consequences can be translated into ultimate
('onsequen('es within the context of natural selection and evolution. We can use the
rrtodel to draw a parallel between instrumental conditioning and natural selection
t S k inner, I 98 1 ; Rosenberg, I 984) by envisioning positive reinforcement in the sense
,,1' increasing individual fitness and punishment in the sense of decreasing fitness.
. . . species-specific patterns are shaped by natural selection as operant
behavior is shaped by reinlorcement IGart'iaeta1., 1973;5J
I Ititt is, natural selection will positively reinforce adaptive behaviors by allowing the
lt. nes that contribute to those behaviors to reproduce themselves in future genera-
trorrs (i.e. selfish gene hypothesis; Dawkins, 1976b). Conversely, genes that con-
tribute to disadvantageous behavior will be punished by decreasing their ability to
rr'plicate. The most extreme punishment is death, which immediately reduces that
rrrtlividual's future fitness to zero (unless a molecular biologist decides to clone its
t)Nn ).
'l'lris concept of 'Se/e ction by Con,sequences' (Skinner, 1981) has been developed
l,r scvcral theorists, including Campbell (1956), Ghiselin (1973), Pringle (1951),
Sl'irutcr (1953. l98l) and Simon (1966). Also, Lorenz (1965) discussed the relation-
'lrr1r bctween reinfcrrcement and natural selection, and Pulliam and Dunford (1980)
,lt'siuttctl it modcl to demonstrate how it would operate in a hypothetical predator.
l'ullirrttt ancl l)untt>rd ( 1980) developed their mathematical model based on conse-
, tu('n('cs. ll'ctlback. cxperience and evolution. Their hypothetical cybernetic lizard is
.rlrl1'1., clirssily ncurirl input I'rom eating red ants (toxic:punishment) and black
rnls (;rleirslrrrl lrrslc prositivc rcinforcement), store the information and recall it
'r lrt'n it rtcrtcttcotttttct's lttt lutt.
l',,,1 tll',,1(l llll"
\\ lrt'rt' /',,, , llrolr ol t';tlin1' ;utl ()lt lti:rllr I I
rr lt',u nutl' lr;rttrtrrr'lcr (0 I )
A CONCEPTUAL MODEL OF BEHAVIOR
g:guided most by recent experience (good if ants are in discrete
patches)
1:guided most by earlier experience
P,,:probability of eating ant on trial n:residual innate tendency*accu-
mulated reinforcement experiences
Z,:Reinforcement experienced on trial r (0:ant toxic; l:ant palatable)
Pulliam and Dunford assume that a lizard that has'a genetic program producing
this neural architecture . . . is favored by natural selection, because it leads to the
development of lizards that avoid poisoning themselves' (Pulliam and Dunford,
1980: l3)
As Maynard Smith ( 1982) and Sigmund (1993) have pointed out, it is difficult to
imagine how an animal can translate proximate consequences into fitness. In fact,
natural selection makes that translation: hence, Maynard Smith operationally
defined the process, as follows:
An animal which performs the 'correct' action - correct in fitness-
maximizing terms - when simultaneously experiencing hunger, thirst
and sexual motivation, will, by definition, leave [the]most offspring.
I Maynard Smith, l9B2 ]
Staddon expressed the same concept in slightly different terms.
. . . things that are 'reinforcing'in the definitional sense of 'strengthening'
behavior. must also be things that in the history of the species have
promoted inclusive litness; that is, if it leels good, it probably is good
(or was good, at least, for one's ancestors) I Staddon, I 980 : xt,iii J
There are potential pitfalls to avoid when using the rnodel to conceptualize selec-
tion by consequences, including:
t Not all characteristics of a species (especially. all behavior acts of an indi-
vidual) are adaptive and have been selected fbr (Adaptionist F'allacy';
Lewontin, 1 979; Johnston, 1985 ). In other words, not all behaviors that
are positively reinforced are necessarily adaptive (Skinner, l98l ).
u It is the genotype which leads (at least in part) to the behavior which is
selected. not the behavior which leads to the consequences (e.g. Dawkins,
r e84).
: It then follows that'Consequences may be beneficial. yet not pnrvirlc
material for the action of naturalselection . . .'(tlinrlc. l9tt2: lrig.l-1).
Sclection by conscclucnccfi (rrrrtl contirtgcrrcics see lrclow; is tlrt' ltirsit' llrt'rrrrsr.'bclrirrtl tlplittutl lirlrpirrp' lltt'ory. llrrrt is. lrrtitttlrls il'lrir'lr (';1rv I'r'p!'s l)r()1r()t11,'
l)l()l)('l';lss(':islll('lll ()l ('ll('tl'\ ('\l)('il(ltlillr'\('t\il\ l)ostlt\t'tt'iltlott t'lttt'ltl (('il('ll'\ l';iln
A MODEL FOR A BEHAVIORAL ACT
Table 2.2. Contingencies e.ffective in protlucing the four basic consequences o/'
behavior
Consequences Effective contingencres
Extinction
Punishment
N egative reinforcement
Positive reinforcement
SR* does not.fbllow any occurrence of the behavior
SR /bllov,.r every occurrence of the behavior
SR does not.follo-* any occurrence of the behavior
SR* follotvs after various time intervals or
occurrences of the behavior: these include:
Fired rutio
Fixed interval
Vuriable ratio
Variable interval
rrr lbod) and punishment (predator risk) will leave more offspring. Of course, there
lurvc been critics of the concept of selec'tion by con.sequence.r (e.g. Catania and
lllrnad, 1984). Finally, I will pass along a caveat sent to me by Dale Lott after he
lrrrtl reviewed this chapter: 'There is selection for a population of genes, and there is
',e lcction of a repertoire ol'operant behavior patterns, but the mechanisms are only
,rrpcrlicially similar and pressing the analogy this lar will confuse students'.
Contingencies (sc'hedules o/ rein/brcement )
r',rrrtingencies are the ways in which behavior and reinlorcing stimuli are paired
i\trrrltlorr, 1980). Contingencies are also called schedules oJ reinfrtrcement (Ferster
,rrrrl Skinncr. 1957). Only certain contingencies are effective in modilying behavior
| ,r lrrotlrrcing the consequen('es discussed above (see Table 2.2).
l lrcsc lirr.rr basic contingencies for positive reinforcement produce different rates
,,1 lrt'lurvior'. Ilutio contigencies are based on the number of occurrences of a behav-
t,tr lrttt't't,u/contingenciesarebasedontheamountoftimethathaspassedsincethe
l.r ,l rentlirrcctl occurrcnce o1- a behavior. The number ol occurrences (ratio) or the
r rrrr(' ('lirl)scrl ( intcr.val) catt bc cither.fixecl or variable.
llrt'st' lirtrr corrturgcrrcics are combined (in the laboratory and, perhaps, in
rr,rtu rt') irr vrrr iorrs wirys to crcatc. lirr example, multiple, mixed, chained and tandem
, lr,',lrrlr's ol rcirrlirrccrrre rrt ( liirrttirto and Logan , 1979). When different contingen-
, r,', ,rp1rly, ;rt llrt'strrrrc linrc lo tlrllcrort hchitviors. or the same behavior in different
, rr11l1'rl:. llrt't lrrt'rt'lt'rrt'tl loirs('()rtt.ur.r'cttt scltctlttlcsol'r'cilt(ilrcement. Concurrent
, lr,',lrrlcr;rrt'llrc lr;rsis ol slrrrlir's ol'olrtirrrrrl lirrrrg,ur1,. itt plttcltcs ol'prcy with cliffler-
, rrI ',r ltt'rlrrlt",,rl tt'tttlt)t( ('ltl('lll
A CONCEPTUAL MODEL OF BEHAVIOR
2.3.5c Leurning paradigms in the model
I agree that 'the world of animals is not a gigantic "Skinner Box" in which they
gradually learn, by trial and error, whai to do and what not to do' (Dawkins,
1986:60). Trial and error learning(operant conditioning\ and classical conditioning
are only part of the animal's capacity to deal with its world. Other learning related
phenomena, such as insight, latent learning, discrimination learning, habituation
and sensitrzatron, also occur and can be encompassed by the model. Also, the
Model is not subsumed within general process theory (e.g. Skinner), rather its flexi-
bility concurs with Roper's ( 1983) statement that,
. . . observations of natural learning tend to encourage the view that
learning consists, not of a unitary general capacity, but of a collection
of specialized abilities which have evolved independently in particular
species to do specific jobs I Roper, 1983:205 J
The model does not assume that the types of learning involved can always be
clearly distinguished. For example, Davey (1989) argued that in a typical classical
conditioning study of salivation (e.g. Pavlov, 1927), it cannot be determined
whether the dog salivates to the bell because the bell is associated with lood or
because the food pellets reinforce salivation. Likewise, the relative role of classical
and instrumental conditioning in filial imprinting remains unclear (e.g. Davey,
1989;Rajecki, 1973).
Also, the model does not assume that classical and instrumental conditioning
are mutually exclusive and work independently. In fact, the model encourages the
researcher to consider both in behavioral analysis, as the lollowing illustrates:
The sight of a stimulus associated with lood elicits, by a process of
classical conditioning, an appropriate set of consummatory responses,
but aspects of these responses may then be modified as the animal
learns the correlation between variations in its behavior and variations
in its success. Both processes are adaptive, for the opportunity lor
successful instrumental conditioning would probably not arise withourt
appropriate classical conditioning in the first place . . .
IMuckittto.rh l9ll.] l6ti I
Researchers should also realize that we cannot directly observe lcurning hut curr
only infer it from a change in behavior, called'performance'(Davcy. l9tt9) Wc also
recognize that learning results in a change in thc aninral's irnatorrry lrnrl 1'rlrysiology.
that is. thc ncrvttus systctn is usctl lirr thc rcccipt. st()r'irg,c (rrrcrrrory). ;rrrrl re tlier,'lrl ol
irt [irrnurt iorr.
A MODEL FOR A BEHAVIORAL ACT
2.3.6 Feedback
Feedback makes the model a closed-loop system (Pringle, 1951; Manning and
Dawkins, 1992; McFarland, l97l;Toales" 1980) which is necessary for any compre-
hensive behavior model.
. . . all the phyla of animals which have evolved a centralized nervous
system have hit on the 'invention'of feeding back to the mechanism
initiating a behavior the consequences of its performance.
ILorenz, 198I:70J
The model provides./e edhack from the ('onsequen('es of behavior to the animal in
the lorm of infbrmution which allows it to update its experience (association
between stimuli, behavior and consequences) and modify expectoncies through
some'internal representation'(Hinde,1982, Ethology, Davey, 1989) which we call
nremory.
. . . Sx [a reinforcing stimulus] acts backward, like a feedback, I suppose,
to produce expectancies. . . . the quality of what the animal expects
importantly influences its behavior. I Bolles, l9BB.450l
Positive and negative feedback lorm two basic types of expectancy which direct
rrnimals to perform behaviors which result in receiving positive reinforcement and
rrvoiding punishment, respectively. Expectancies come into play when the animal is
rrrotivated to perform a particular behavior.
. . . both associative and motivational lactors may contribute to making
some activities readily performed when they are reinlorced or readily
suppressed when they are punished. I Shettlewortlt, I 983 :23 J
2.3.7 Feedforward
I lrc nroclel recognizes that the next behavioral act in the continuous stream of
lrclurvior citn be elicited by the consequence of the behavior that precedes it (i.e.
rr'irrlirrccr'-clicitccl behavior'. Davey, 1989:201). For example, aversive reinforcing
,lrnrrrli gcncrally clicit behaviors which allow the animal to escape the punishnlent,
',rrt'lr rrs spilting out tlistustcfirl lbod.
l"ectllirrwirrtl irlso occurs in a chain of behaviors (e.g. search, capture, consump-
Irt,n ol'ptey)ls tlcsct'ibcrl by Ilinclinc (1988) in his commentary on Gardner and
t irrrrlrrt'r' ( l()l"iS):
As rlt'st trlrt'rl llry ( i;rttlttr't ltntl ( lltt'tlttct' i9tilll. 'll'etllirrwlrrtl'concerns
Itt'llrt t,,t ('n\ lrotttttr'ttl tr'lltliotts itt tr lrit'lr ()nr' sittt;tliott cvrtkcs lut
38 A CONCEPTUAL MODEL OF BEHAVIOR
Causation
Exogenous
stimuli
v
APPLICATION OF THE MODEL
'fable 2.3. Where Tinbergen's.fbur areas oJ-study are incorporated in tlrc modelfor a
ltchqvioral act
Areas of study Relevant portions of model
Positive feedback
l-----
--?--) Behavior
+ Behavior
- OntogenY
\a- 
-at'-----___ ----'
Negative feedback
Function
Consequences -) Feedforward
(Contingenctes)
liunction
('ausation
( )ntogeny
Irvolution
Proximate Consequences;Feedback
Exogenous and endogenous stimuli; feedforward
Behavior changes during maturation; these result from
changes in environment, experience, anatomy, physiology,
stimuli, and consequences.
Genotype; often studied using comparative studies of the
behavioral phenotype (i.e. Behavior)
Evolution
Fig. 2.5 Where Tinbergen's areas of study fit into the Model for a behzrvioral act.
organized pattern of action resulting in a new situation that evokes a
different pattern of action resulting in yet another situation, and so on.
This type of behavior-environment relation has long been described as
applying to behavioral chains based on positive reinforcement.
IHineline, l9BB:457]
My use of the term feedlorward is somewhat different. but not exclusive of its use by
Toates (1980) and McFarland (1971:102) as a'phenomenon which enables an
animal to anticipate the long-term consequences of behaviour and to take appropri-
ate action to forestall such consequences'. That is, an animal that is not thirsty
might still drink in anticipation of a luture water deficit (McFarland,l97l).
2.4 APPLICATION OF THE MODEL
Below are examples of how the model can be used as a basis for: l. conceptualizing
the areas of study (Chapter 1);2. organizing the types of question (Chapter I ); 3.
locusing research; 4. developing an expanded or more focused model; and 5. diag-
nosing and treating behavior problems. Chapter 5. on delineation of research,
describes how the model can assist in defining questions, objectives and l-rypotheses.
2.4.1 Conceptualizing the areas of study
Tinbergen's four areas of study (Chapter l) can be locatecl itt portiorts ol'tltc tttrttle I
(Figure 2.5, Table 2.3). This assists the rescarcher in sccing how ltis 1'ritt'licttlitt
research intercst fits into lhc'big picturc': thal is. how il irttcgnttcs willt otltct :ttt'rts
ol'stucly.
llxltnrplt's ol tt'st'lrtt'lt tlr;rt lirr'rrst's otr ltrltliolts ol lltt'lttorlt'l tt'lt'rltttl lo t':tt.lt :ttt'lt
ol sl ltrlV itt(' l)tovlrlt'rl lrt'l, rrv
When/Where
Exogenous
stimuli
\
Positive feedback
k-'-'---
--i-, Behavior 
-"
+ Behavior -)_ Whatfr''... ,''t-- 
-.a'----------
.. whv
Consequences'-) Feedforward
. (Contingencies)
Who/How Negativefeedback
I iu 2.(r Where the six types of questions about behavior fit into the model fbr a
behavioral act.
2.4.2 Organizing the types of question
I tr:,rtrt: 2.6 illustrates where the types of questions discussed in Chapter 1 are
l,rr'ttsctl in lhc nrodel. The first question to be answered in any research project is
,rltvrtys 'What docs the animal do?'. The model demonstrates that all the other ques-
rr()rts iu'c tlircctctl at lactors that affbct what an animal does (see Table2.4)
2..1..1 lirrcusing rcscarclr
ll,ttttt1, tlt'lcttnnrctl tlrc irt'cit(s) lo bc strrcliccl ancl typc(s) of Questions to be
.r,l.ltt'sst'tl. t('\(';rtt'lt tltr'rt lrr't'rlr))r's locrrsctl ()n ()nc. ()t't)t()rc. pitrts ol- the rnodel .
l(t'1'.il.llt':.s,rl ttllrl l)(rtltorr rrr.'lir(u\()lr.lr'st';rt't'lr l('sillts(lty rrcccssily)trlwirys rCllrtC
l,,tr L lrr lltt',tlttttt,tl'., lrt'lrtvtot. tr'. tllttsllrlt'rl rrr llrt't'rlrttrPlt's llr'lorv
(G+E+D+(A+P)
(G+E+D+(A+P)
A CONCEPTUAL MODEL OF BEHAVIOR
Table 2.4. Where the sir types of questions are incorporated in the model.for u
behavioral ac't
Types of question Relevant portions of model and examples
What?
Who?
Where?
When?
How?
whv?
Behavior
(e.g. courtship and territorial display)
Anatomy, physiology, environment, genotype
(e.g. large, healthy and motivated to breed, dominant,
male sage grouse)
Exogenous stimuli
(in central territory, on breeding ground in North Park,
Colorado with other males and females)
Exogenous stimuli, endogenous stimuli
(spring breeding season; Courtship behavior in presence
of females; Territorial displays in presence of males;
reproductive 'drive')
Anatomy and physiology
(endocrine and nervous system stimulate and integrate use
of wings, tail, legs and gular sacs in 'strutting'and
'booming' displays)
Proximate consequences, ultimate consequences
(Hedonistic value of displaying and mating to the
individual male; a male whose displays allows it to hold
a central territory and attract and mate with females
has a higher fitness)
Genotype: Ralph and Menaker ( 1988) found a mutation in hamsters in
which v,ild-type (normal genotype) animals have a circadian locomotor
rhythm of about 24 hours; heterozygoas animals have rhythms of about 22
h, and animals hontozygous for the mutation have rhythms close to 20 h.
Environmen r: Holekamp and Smale ( 1993) found that the prc.st'nt't' ttf
mother spotted hyaenas (Crot'uttt c'rocutu) during their oli.spring's ilgg,r'cs-
sive interactions strongly influenced the outcomcs lirr.juve nilcs lcss lhirrr (r
months of age.
Artulonn,'. Chouclhury and Illack ( l99.ll sttrtlicrl ttutlc sclct'tion in ('ill)lt\'('
birrnirclc gccsc (llrttttttt lrtrt'tt1t.ti,t'1. 'l'ltcy lirtrntl llrrrt ltt'ttvit't lt'tttrtlt's ltntl
lltosc rvitlt r/,lll, t't'f(t( t'ltrtllt't n.t srttttPlt'tl sl1,1ti1ir.",ttllv lttr)t('lxrl('tllt;tl
ttt;tlt's
APPLICATION OF THE MODEL
Physiology: Landsman (1993) studied sex differences in electric organ
disc'harge in a weakly electric fish (Gnathonemus petersii).
Exogenous stimuli: Nicoletto (1993) studied the effect of male ornamenta-
tion and display rate on the sexual response of female guppies.
Endogenous stimuli: Dethier (1966) describes how distention in the
foregut of a blowfly sends a messoge via the recurrent nerve to the brain,
which inhibits extension of the proboscis, thus inhibiting further feeding.
Behavior: Fraser and Nelson ( 1984) described the frequencies and
sequencing of l6 c'ourtship behaviors in a Madagascan cockroach
(Gromp hador h ina p or t ent o sa).
Consequences: Shettleworth (1978a,b) found that scrabbling behavior in
hamsters increased in rate when positively reinforcedwith seeds and
decreased in rate when punishedwtth mild electric shock.
Contingencies: Krebs et al. (1918) determined the loraging strategies of
great tits (Parus maior) in two lood patches with different densities of
mealworms (i.e. variable ratio schedules of reinforcement).
Feedback: Brown and Gass ( 1993) demonstrated that rufous humming-
birds (Se/a sphorus rufus) learn spatial associations between cues and
rewarding feeders.
Feedfrtrw,ard: Lawhon and Hafner ( 198 I ) led seeds (millet) and seed
mimics (glass beads) to kangaroo rats (Dipodomys) and pocket mice
(Perognathas). They found that glass beads were always rejected
(rather than pouched) after unsuccessful iltempts to husk them.
2.4.4 Developing an expanded or more focused model
I hc modelcan be expanded to include additional lactors or focused on portions of
nrorc importance to the researcher.
)..t..tu Expanding the model
I lrntle ( l9ll2). in his discussion of behavioral development, proposed a model of the
rt'lrrlionship bctwr:e n ontogenetic and causal factors and consequences (Figure 2.7).
I lrrrrlc's rnorlcl incorporatcs a route of action for ontogenetic factors that I have not
,1rt't'ilicrl irr nry rrrorlcl. IIowever. I have identified ontogenetic factors in section
' I I . I lintlc lrrs rrlso inclrrrlerl (but not labeled) f-eedback (from functions to ontoge-
r('lr('lir('tors):rrrtl li'ctllirrwirrtl(ll'orn gouls ttl cliciting factors).
42 A CONCEPTUAL MODEL OF BEHAVIOR
Coneequences
Fig.2.7 Relationships between ontogenetic and causal factors and consequences.
The distinctions between ontogenetic and predisposing and between predisposing
and eliciting factors are often somewhat arbitrary. Among the consequences, the
categories of reinforcers, goals and functions only partially overlap. Although
a goal is normally achieved as a consequence ol a behaviour, an internal
representation (anticipation) may contribute to causation (dotted line).
Consequences may be beneficial, yet not provide material for the action ol
natural selection (functions, strong sense). Exceptionally, harmful consequencescan be goals. The dashed line indicates evolutionary consequences on the next
generation (from Hinde, 1982).
2.4.4h Focusing the model
l. The model can incorporate the 'behavior systems' approach (e.g. Timberlake,
1983; Timberlake and Lucas, 1989) to modeling behavior by relating; i. innate
behaviors (modal action patterns); ii. 'motivational states'(behavioral systems); and
iii. exogenous stimuli (Davey, 1989). For example, Davey's (1989:158) organization
of leeding behavior in the rat (Figure 2.8) is incorporated by recognizing that the
behavior system and subsytems are stored, modified. processed and activated (via
endogenous stimuli) within the animal's anatomy and physiology. The model can
then, lor instance, assist in visualizing the proximate and ultimate consequences of
each of the behaviors.
Davey's model is similar in structure to Baerends' (1976) classic model of inter-
ruptive behavior during incubation in herring gulls (see Davey, 1989:320).
2. Alcock (1993) presented a rnodel for the control of circadian rhythms that
incorporates exogenous stimuli, anatomy, physiology, and rhythmic behavior- pat-
terns (Figure 2.9).It focuses more explicitly on what I have labeled in a gcltcral way
as anatomy and physiology.
3. It is possible to focus the moclel on internal motivationul slirlcs rrntl tlce isiorrs
by incorporating more explicit control thcory :rrttl incltrtling cornpiulrlors. t'oll-
trollcrs ittttl scrvottrcchltttisrtts:ts p:u'l ol'tlte ln:rlortty lrrrtl lllrysir)l()p,y (('.1' lo;rlt's.
l9ll0; Mcliitt'llttttl, l()7 l). An exlttuplr' ol lr tttotlr'l u'lrit'lr us('s ;r t'onrp:ulrlor ls
Ilrrttlittl'lirltl's (l()i-i.l) tnorltlir'ltllon ol ,Atr'ltt'l's (l()/(r)tnorlt'l ,,1 lt';l iur(l ;t,','t(",',t(rtl
1a"n"r,"i,,
l
]ueutrat
-|Harmful
Predisposing
factors
BEHAVIOR
SYSTEM
APPLICATION OF THE MODEL
SUB-SYSTEMS MODULES OR EXTERNAL
FI"ED ACTION RELEASERS
r____; ___ _____-_.ff:-r lll
gITE-KILL
ANOGENITAL.S}iIFF
FEEOING
BEHAVIOR
SYSTEM
EREAX GR^SS STEMS
TFI^NSPORT IO FOOD SITE
INVESTI64TIVE
FOEAGING
GNAW.BITE OFF
SWALLOW
f soL,o Il--1""*J
liir. -).I'i 'llrr'lirtcliotutl orgltttizlrlion ol-a putativc ltc'cling behavior system for the rat
( ll orrr I )ltve v l ()li() ).
fr---r, I
i -'l onel cues I
, L-)
A CONCEPTUAL MODEL OF BEHAVIOR
ENTRAINMENT
PATHWAY
SUMMARY
OBSERVED
RHYTHMS
lnfluenced by
size of discrepency,
hormone levels,
past experience
in fights etc.
lnfluenced by
'hormonal state,
location of
stimulus etc.
trig. 2.10 Motivational models using control theory; a simplified version ol a control
theory model of aggression and fear in vertebrates (from Huntingford, 1984).
EXTERNAL STIMULI
( isol ate, e liminate, de sensitize)
SURGERY
kaslralbn)
CONSEQUENCES
(maintain, modify)
'l' pos. REINIr)RCEMENT
--1) NEUTRALORSUBMISSTVE 2t NEG RETNFORCEMENTt,/
-z) AGGRESSION (type?) ./
\. rulvrsrtMENr" EXTIN('T'ION
talts I l{t( "t t()N
tnttt. . lr' Atrttttl)
I rt' ' I I \,1111 1'l llrr'l,tt lol .,ttt.tIIl1r'rl t'llt,rl,'l,r',1 ttttl,lrl t,n,,t(l(.t tn,lltl'tt,rstttl,lttttl
llr.llllrl,,tlt.t),1'tr'..trrn lrtillrlr'ilr til,t rlill,lrlr,trrrrrl,l'1 lll, trrl,t Ktt.t;r1r)
6Dlenvironmental cues I - | receptors f- (_/
CLOCK
MECHANISM
Fig. 2.9 A master clock may, in some species, act as a pacemaker to regulate the many
circadian rhythms of an individual (from Alcock, 1993, after Johnson and
Hasting, 1986).
in vertebrates (Figure 2.10). Huntinglord (1984) should be consulted lor a thorough
discussion and examples of various types of models of motivation.
2.4.s Diagnosing and treating behavior problems in animals
The model can be used by applied animal behaviorists as the basis for determining
the etiology of a behavior problem, what is maintaining it, and what manipulations
can be made to mitigate or eliminate it. For example, Figure 2.1 I illustrates how the
model can be used to organize some of the factors to be considered in diagnosing
and treating an aggression problem in dogs.
2,5 SUMMARY
The model presented above is the result of my attempting to provide a structure on
which ethological research could be designed and conducted. I have lound it uselirl
in assisting graduate students in designing research by getting them to recognizc thc
various factors, past and present, which contribute to behavirtr.
For the behavior (what) of interest, you can'plr"rg into'the rnotlcl whirt yotr h:rvc
learned from the literature about the variables tliat allcct that bchavior'. I,or llre
types of question (e.g. where'l whcn'/)y()r.r arc rttcr)rplirrg lo illlswcr. y()u cln bclin lrr
identify the variablcs (c.g. gcnotypc. cntlogcnorrs slirrrrrli)tlurt;rrc lrkelv lo lr;rrt.rr
l-llit.itlr cll'cct ()lt y()ul't'csttlls. Vrrr clrrr prrl (lre lllrrlitrlly r'onrplt'lt'tl rrtotlr.l orr llrr.
lllltckltoltl'tl ;tlttl ltt:tiltslot ttt u'tllt t'ollr';11,11r's lo itlt'rrlill lrrlrltlt()lrill r;rr r;rlrlr.s 1t. 1'
t'\o|1'11,rttsslttttttlt)ttlttrlrrltottlrllrt't,,trit,lr'rt'rl;rttrlPo11'gllr;rlrrrt'llr,,rl,,,,l trr,rrrrIrr
l,rl ttr1,. nr('.t'.ulnl, or r'lllnt,tl ntl, l lro,,r' r,u r,rlrl...,
(if discrepancy >> 0)
ORIENTATION
RESPONSE
ENVIRONMENTAL
CONSEOUENCES
OF BEHAVIOUR DECISION
PROCESS 2
Escape or
immobility?
Sensory input
no longer impinges
on animal
Sensory input
switched off
46 A CONCEPT'UAL MODEL OF BEHAVIOR
In tirne, as most of the terms in the model become replaced with real variables,
you begin to have more confidence in your grasp of the complexity of the research
you are proposing. You can pose more clearly defined questions, lormulate rnore
exacting hypotheses, and begin the task of detennining how you will answer those
questions and test those hypotheses. That is what the rest of this book is about.
3 Choice of subjects
Ethologists corre to study particular species for various reasons, but all generally
travel via two routes: l. their special interest in a particular ,species; or 2. using a
species that is suitable for investigating a particular rcncept. These two routes inter-
twine so that a researcher may become interested in pursuing a concept after having
studied various aspects of a species'behavior. Likewise, a researcher may initially
study a species in pursuit of answers to a conceptual problem and become fasci-
nated with other aspects of the species'behavior.
3.I SPECIES-ORIENTED RESEARCH
Many ethologists who settle on a particular species to study are naturalists who dis-
cover a fascinating species while spending time in the field. The following excerpt
l'ront C'uriou,y Nuturuli.vr.r describes how Tinbergen began his many years of research
( )n the digger wasp:
On a sunny day in the summer of 1929 I was walking rather aimlessly
over the sands, brooding and a little worried. t had just done my finals,
had got a half-time job, and was hoping to start on research lbr a
doctor's thesis. I 'wanted very much to work on some problem of animal
behaviour and had lor that reason rejected some suggestions of my well-
meaning supervisor. . . .
While walking about, my eye was caught by a bright orange-yellow
wasp the size of the ordinary jam-loving Vespa. It was busying itself in
a strange way on the bare sand. With brisk, jerky movements it was
ra,alking slowly backwards. kicking the sand behind it as it proceeded.
'l"hc sancl llcw away with every jerk. I was sure that this was a digger
wasp. . . .
I w:rtcherl thcse wasps at work all through that afternoon, and soon
bccrrrrrc rrbsorbcrl in lincling out exactly what was happening in this busy
irtscct tort'tt....
;\s I rvrrs rv:rtching thc wusps. I began to realize that here was a
rvontlcr lrrl ()l)l)()r'l trrrill, lirr rloing cxactly thc kind of field work I would
lrkt'lo rlo llr'r'r'rvr'r't'ntluty lttttttlt'ctls ol'tliggcr w:lrips cxttclly wltich
\l)r't tr's I tlrtl rrol lirros'rt'1. lrrrl llr;rl rrotrltl ttot llr'rlillictrll lrl lirrrl r)ul. . . .
l\lr rr()nr('\ \\'('r('('rr't. I Lnr'\\'\\lt;tl I tt'ltttlt'rl l,ttlo. lltis tl;tr'.;rs il
CHOICE OF SUBJECTS
turned out was a milestone in my life.For several years to come I was to
spend my summers with these wasps . . . [Tinbergen, 1958.5 8J
Dethier, who spent many years pursuing the behavioral biology of the blowfly,
describes how he settled upon the blowfly as a research animal in the following
excerpt from his delightful book, To Know a Flv:
When choosing an experimental animal, therefore, why settle for
anything so prosaic as the laboratory rat, so giddy as the guinea pig,
so phlegmatic as the frog, so reptilian as the chicken, so cousinly as the
chimpanzee? Why not choose an excitingly different creature like the
aardvark or the dugong'? Why not choose the fly?
With so many kinds of flies in nAture's burgeoning storehouse of
life, how does one choose a proper species for study'l The answer is
simple. Let the species choose you. This was how our laboratory came
to work with the black blowfly flfteen years ago. I Detlier, 1962:7 I J
The rest of Dethier's account of his early years of research on the blowfly makes
heuristic and enjoyable reading.
Von Frisch, a nobel laureate along with Lorenz and Tinbergen, began his many
productive years on the study ol'bees through his attempt to'set the record straight'
regarding the color vision of bees. Von Frisch describes the launching of his career
of bee study in the preface to his fascinating book, The Dant'irtg Bees:
. . . some forty-five years ago . . . a distinguished scientist, studying the
colour sense of animals in his laboratory, arrived at the definite and
apparently well-established conclusion that bees were colour-blind. It
was this occasion which first caused me to embark on a close study of
their way of life; for once one got to know, through work in the field,
something about the reaction of bees to the brilliant colour ol flowers,
it was easier to believe that a scientist had come to a false conclusion
than that nature had made an absurd mistake. Since then I have been
constantly drawn back to the world ol the bees and ever captivatecl
anew. I have to thank them for hours of the purest joy ol discovery,
parsimoniously granted, I admit, between days and weeks of clesplir
and fruitless effort. I llnr I"ri.tt'h. 19.t.]:iii I
Some researchers have begun their studies in animal behuvior otr u sirtglc s1'rccics
and then become interested in a limited type of behavior which lltcy hirvc ge ttct'itl-
ized to other species. For example, Allee recoLlnts how lte bcgittt st trtlying ll'cslrivrttct
isopods and then became interestcd in sociul bclritviot'itt gcrtct-rtl.
Alntrlst lirrty yctrrs itg() lts tr gnrtlrurtc sltttlcrtt itt zoololll l u';ts cttl'.;tl't'tl
irt slrrrlyirtp, tlre lrr'lurvior ol':i()n'r('('()nrnl()n :.inurll lrcslr rvrtlt't lttttnt;tls
t'lrllt'tl isollotls rl;tt';lllt't tl:tV l Prrt lols ol lirt'()l l('ll l\()l)o(1" tttltr
SPECI ES.OR I ENTED RESEARCH
shallow water in a round pan. . . . when a current was stirred in
the water the isopods from the streams usually headed against it; but
those lrom ponds were more likely either to head down current or to
be indifferent in their reaction. . . .
Rather cockily I reported after a time to my instructor that I had
gained control of the reaction of these animals to a water current. By
the judicious use of oxygen in the water, I could send the indifferent
pond isopods hauling themselves upstream, or I could induce the stream
isopods to going with the current. I had not reckoned with another
factor that presently caught up with me.
After a winter in the laboratory it seemed wise as well as pleasant to
take my pan out to a comlortable streamside one sunny April day and
there check the behavior of freshly collected isopods in water dipped
from the brook in which they had been living. To my surprise, the
stream isopods, whose lellows all winter had gone against the current,
now went steadily downstream or cut across it at any angle to reach
another near-by isopod. When I used five or ten individuals at a time,
as I had done in the laboratory, they piled together in small close
clusters that rolled over and over in the gentle current. Only by testing
them singly could I get away from this grolrp behavior and obtain a
response to the curretrt; and even this reaction was disconcertingly
erratic.
It took another year of hard work to get this contradictory behavior
even approximately untangled; to find under what conditions the
attraction of the group is automatically more impelling than keeping
looting in the stream; and that was only the beginning of the road that
I have followed from that April day to this time, continuing to be
increasingly absorbed in the problems of group behavior and other
mass reactions, not only of isopods, but of all kinds of animals, man
included.
As the years have gone on, aided by students and other collaborators
and by the work of independent investigators, I have tried to explore
cxperinrcntllly the implications of group actions of animals.
IAllee, 1938.5 7J
Allcc pursuctl lris irttcrcst in the social behavior of animals and became an early
;rrtrl inllttcnti:rl ctlrologist. Thc unusualevents that led to E.O. Wilson's selection of
rrrsccls. cspcciirlly itttls, lrs his lircus of study are recounted in his revealing autobi-
,,1it'ltpltl'(Wils,rtt. 199-+). Insight into how severul other noted ethologists selected
lltr'it tt'sr'rttt'lt sP1'1'1q'5 t'lrn ltc lirrrrrtl in I)cwsbury's (198-5) cttnipilation of autobi-
,,;,I;t;rlIlt's
l,llr,,l,r1,rsls ollt.n lrr.t.olrrt.rlt.r.Ply rrrlr.rr.slt.rl in Plrrlicrrllrr sllccics:rrrtl lrrrr.srrc rlil,
It'lt'ttl ltttr". ,rl r;ttt'rll()n\ 't\, lltt.\ :ru.,(. \\ ltrlt. ,,llt(lvltl' ollrt.t ;rs1lt.r.ls ol lltt. sltt.r.it.s'
50 CHOICE OF SL]BJECTS
behavior. The cliche that 'research generally provides more questions than it
answers'keeps some ethologists studying one, or a few, species for their entire career.
This is olten efficient in that they can build on past experience with the species and
are able to make ellective use ol their time.
3.2 CONCEPT-ORIENTED RESEARCH
Although Lorenz came to study birds, particularly waterlowl, as an outgrowth of
his apprenticeship with Heinrotli, he selected species with an eye to unraveling anal-
ogous and homologous relationships in patterns of behavior. Nisbett describes
Lorenz's choice of subfects this way:
However his interest in an animal may have arisen in the first place - and
this may in part have been by the interplay of change and curiosity - his
chosen subjects did in lact lorm a coherent and rational array. The
different species lell into several groups. First, there were those wliich
were in their own right the central objects of his study; initially the
jackdaws, then the herons, and now the geese. Second, were the closely
related species: ravens lor comparison with jackdaws. or mallard ducks
to watch out of the oorner of an eye wl-rile looking at geese. These
showed not only what the ducks had in common with their geese cousins
but also what they had developed diff.erently: he could ask himself
'why?' Heron society was markedly dilferent from that of jackdaws or
geese; again 'wliy'l'Then there were the species unrelated to jackdaws or
geese. but which liad similar elements of behaviour. This allowed him to
look for patterns of behaviour to which evolution came indepenclently in
different species. INi.sbett, 1977:44J
In some cases, researchers discover concepts that can be tested on their f avorite
species. In other cases, previous research on ar species reveals aspects of its behavior
which make it suitable lor testing a concept: this is illustrated by Alcock's 1lt)73)
use ol red-winged blackbirds to test L. Tinbergen's (1960)'searcl-r imagc hypothc-
sis'. Ettrlier work with the species had suggested that thcy might selectivcly seitt'clt
in patches where they had lound lood previously, but more importitntly lix' Alcock
they were omnivorous ancl available. Therefore, he used this spccics in rttt cxpcti-
mental tbod maze to elnswer the questions'do bircls lertrrr wltct'c llrcy rrrc likcll lofind lood and come to use locational cues to clirect thcir scarcltittg ruttl/ot'tlo bittls
learn what lood they are likely to fincl itncl cor.t.tc to scurclt 1.rt'clL't'cttlirrllv lir llrrrt
item on the basis ol'visual cucs irss()ciatctl witlr tlrc lirotl'l"l'ltc birtl irr tlris (irs('\\'ir\
thc rcrl-r.vingcrl blirckbirrl. ()llrcr lcse;uc'lre r':; llrr,'c lr'slr'tl 1.. I rllrt'llt'tt'r lt\'po1l11'11''
()ll (':il litrn t'to$S (( .,, lt/\ ( (,t(,ilt'. ('l()./('. l()70). (l()lll('\ltt r'lttt k " 1(,,tlltrt t',tlltrt.
l)rrrrktn:. l()/l);rtt,l 1'tt',rl ltl', ll'rttu\tttttlt,r.l(o\;ttltlt l()/())
CONCEPT-OR I ENTED RESEARCH
3.2.1 August Krogh principle
Researchers who pursue answers to conceptual questions or concentrate their
ellorts on a particular type of behavior attempt to study species that best represent
the concept or type ol behavior under stucly. In 1929 August Kragh stated that 'For
a large number of problems there will be some animal of choice. or a few such
animals. on which it can be most conveniently studied'. Krebs (1915) has labeled
this statement'The August Krogh Principle'.
The indigo bunting was selected by Carey and Nolan (1975) to tesr the
'Verner-Willson C)rians hypothesis' that polygyny would evolve in avian species
where critical resources are distributed ir-r widespread patches, if the advantages of
one male mating with several lemales offset the disadvantages of reduced parental
attention and possibly increased attraction of predators arnd depletion of food
resources. Preliminary study of an indigo bunting population in Indiana had led
Carey and Nolan to predict that the poptrlation would be polygynous erncl therefore
provide a good opportLrnity to test the hypothesis.
Experimental psychologists traditionally use rats, pigeons, or selected primates
as their subjects in studying learning theories that they believe will then be applica-
ble to (or at least worthy of testing on) humans. Two reasons are generally given lor
pr-rrsuing concepts of learning on such f-ew species. First, many psychologists
suggest that learning processes are basically the same in all species, differing in
itmount rather than kind. These species are being used as biological models in essen-
tially the same way that the drug industry uses rats and mice to test drugs designed
lirr human consumption. Second, there is a wealth of background data already
available on these species. It is questionable whether the August Krogh principle
was invoked when the rat was selected for the early psychology studies. It was prob-
rrbly cottvenience that initiated and maintained the momentum that established the
nrt as the psychologist's choice subject (Beach, 1950).
Several yeitrs ago while cooling olf in a local pub (after a hot afternoon observ-
ing yellow-hcttclecl blackbirds in a nrosqnito-infested marsh), Dr. Gordon Orians
crplttitled to.l. R. Watsort ancl n-ryself that he had become very interested in the slugs
tlrirt lttragccl irt his hackyarcl garden in Seattle. His interest was more in testing eco-
logicirl lhcory thitn irr sitving his vegetables. Later Cates and Orians reported on
tltcir lcsl ol'lltc ltypothcsis lhal 'early successionalplant species make a lesser com-
rrritrncrr( ol'rcsorrrccs to (lcl'cllrl agitinst herbivores, ancl should then proviie better
lirotl resorrrt'es lor gcrrcnrlizctl lte rbivorcs than later successional and climarx plants,
((';tlt's:tttrl ( )ti:tlrs l()75:-ll0). Wh:rt worrltl l-rc ir goocl rcscurch anintal on whicli to
It'sl l lrt'st' pr t'tl rt'l lol)s.) ('lrlr.'s lr rrtl ( )r'itr rrs er ;tllr irr:
( ir'lrt'r;rltzt'rl lrr'r lrrrr)t('s iil(' t('(lilrrr'rl lor lr'slrrrl' llrt.st. lltr'rlit.liot)St \I,C
ll,t\,'lt',,',1 ttt ,,ttt ('\l)('ll1t('11', ltto,,;)('( t(.,, r,l ,,lrrl,,, lrp1l1 Irllp11 11 lrr 1,1.,r..'
5l
Table 3.1. Credit-debit sheet of some characteristics to be considered when selecting a subject species
Characteristic Questions Credit Debit
Suirtthilitt'
1; tiluhilitv
1,i-;n r uhilitt
B _.- -.,tr, tttfitl
,'' riliLl'tit.)n
-\'.,i'r;_,.'i',
Is the species suitable for the concept being studied (August Krogh principle)?
Can you recognize individuals by natural marks or can they be easily marked?
Does it engage in interesting behavior which you can observe repeatedly?
Can you make the necessary manipulations on this species?
Is the species found locally or will you have to travel to study it in the field?
If it is found in a foreign country, what are the political ramifications?
If you want to observe the species in the wild, is it accessible in its habitat?
Can observations be easily made without altering its behaviour?
Is it nocturnal or diurnal?
If you want to bring the animal to you, can it be easily obtained?
Is it on the rare and endangered species list?
Can it be easily captured?
Can subjects be replaced if they die?
Can individuals be returned to the point of capture when the research is done?
How will the animal adapt to life in captivity?
Can you simulate its natural environment and provide for its special needs?
Are its habits compatible with yours?
What is already known about the species?
Is there a reasonable backlog of data on which to build?
Has someone already done the research you are planning?
Hou'does it help you answer the questions above and anticipate other problems?
Total the credits, assess the financial commitment, and accept or reject the species
as \our subject.
\\-iil 1ou be able to lollow the guidelines for animal welfare and ethics in research?
tsee Appendices C and D)
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iAt E:;z* #?cf '-[? st] =a"a g i;E ='ix;: Id I q== ="8;x'serAEE 3 6 sqaqg=E- =;ei*==P+1I-iigiLiEiz i r€i=2=:q ?ie;u[1:+,gI1Ef; $ ]eEg+a=alEl E ?==. =-..: i,.= ?.-;,?i ?E:il?lgie:*f+s=a = !&iE3En a.Nee6:7i =i=!1,-i" 9, =.,6{zA ie:=c7.iivs==3:=: !I a'fisBu. cv L:-='o:s ;:AgaH jTfr !=EB- 3.:o-=3-; €
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HOW TO OBSERVE
while watching they may develop interest in a particular species, behaviors and
questions; but obtaining answers to those questions requires careful observution,v.I
recently watched a goshawk glide from it's perch in an aspen tree and snatch a red
squirrel olf a log using the talons of its left foot. It was a chance occurrence which
was exciting to watch and raised some questions, such as: Do goshawks usually
employ only one set of talons when capturing red squirrels'/ If so, are individual
goshawks primarily left-footed or right-footed? Answers to initial questions, such as
these, usually lead to additionalquestions.
Most visitors to zoos occasionally stop and watch animals. When they leave they
can tell you about many of the animals they saw and some that they watched; lew
can relate any in-depth observations of particular behaviors. Many bird-watchers
see a bird, identify it, and rush on hoping to add more species to their lists.
Observers take the time to study the behavior of the birds, describing in their note-
hooks the intricate details of individual and social behaviors and perhaps recording
the birds' vocalizations lor later relerence and enjoyment. Intense observation is
generally more rewarding than superficialwatching. It is also necessary in the study
of'animal behavior. Observation may be as much a state of mind and awareness as it
is a clearly defined technique. This is reflectedin the quotes in Chapter 3.
Observers must be more than a visual recorder; they must also be aware of input
to their other senses and must think. One must be disciplined enough to know when
to bc a machine-like recorder of data and when to contemplate what is happening or
lrls happened. The experienced and astute observer often develops and 'tests'
lrypotheses mentally while keeping animals under observation. Obviously, attention
to rapiclly occurring behavior is not consistent with theorizing, hence priorities must
lrc established.
l{cscarchcr priorities while observing various behaviors and species in various
lrrrbilats ure generally the same, as flollows:
t ILccorcl clata accurately and completely.
: ('hcck ccluipment to make sure it is working properly and repair it if nec-
cssir ry.
r 'l'hirrk about what is happening. put it in perspective, and lormulate
Irypollrcscs. Think ubout the hypotheses, discard the easily disproven
orrcs. rrnrl lvritc rlown those that call for additionalthought and testing.
I lris t'onsl:rrrt corrsitlcralion ol'hypotheses is a procedure to be used only
n lrt'rr nrrkirrl irritilrl rccortrurissuncc obscrvations fbr the lormulation of
rprt'slrorrs.olrjr't'tivt's;rrrtl lrylrolltcscs. llrlr,vcvcr.s()ntcsitntplingmethods
(( lr:rptt'r l.i ;rrrrrl/or rrlrt'lir itr ,rl'tlrr'lrrrirrurl(s) tuttlct'obscrvlttitrn cittt
l)trr\ rrlt'Pt'r rorl., rlrr nt1'tl;rl;t t ollt't'll()tl (ltll ltlt' rvlrit'lr v()tt ('tttt ltlltlrv V()ttt'-
,,,'ll l,r llrrtrl. ,rl,,r111,r,ltlrlr,rtr,rl,1u(",1r()n',rrtt,l lt\Polltr'rt'r. lrttl ltt'rt'r :tllrlrv
55
4 Reconnaissance
observation
4.1 HOW TO OBSERVE
An early step in the study of animal behavior involves intensive reconnaissance
observation. This may occur befbre you have decided what aspect of behavior to
study and probably befbre you have lormulated any hypothesis (Lorenz, 1935). This
early stage in which you become f,amiliar with the animal's behavior 'is the most
arduous ancl demanding aspect of behavioral study'(Marler, 1915:2).lt is extremely
important, for no successful research can be launched without this background
knowledge. Methods have been suggested lor evaluating sampling plans for longitu-
dinal stuciies of behavior basecl on 'pilot samples' taken during reconnaissance
observations (e.g. Kraemer et ul.,1911).
Besicles helping you to clesign your research, these initial observations also
provicle an important source of additional questions and hypotheses.
Having myself always spent long periods of exploratory watching of
natural events, of pondering about what exactly it was in the observed
behaviour that I wanted to understand belore developing an
experimental attack, I find this tendency of prematurely plunging into
quantilication and experimentation. which I observe in many younger
workers, really disturbing, unless, as happens to come, they do, fronl
time to time, return, more purposefully than before, to plain, though
more sophisticated watching. ITinhcrgL'tr, I 95 I : vi I
Tinbergen (above) talks about 'exploratory watching', 'more sophisticatctl wrttclt-
ing', ancl 'observed' behavior. The terms watching and observitrg ttrc ctltllttrottly
interchanged (see quote from Huxley on p. 113), but I belicvc cthologists slrotrltl
draw a distinct dichotomY.
.l.l.l Watching versus observing
Baby-sittcr-s rvtttlt clriltl pcn: tlcvcloprrrcrrtrrl psyt'ltolop,ists rtlr.tr', t'r' lllt'ltt. ll rrlr ltrttt', t:
lr c:tstltl cp(l(.lt\,()t': ttlr.st,t yitt,t: ls ;t tir,,)t()1s l)t(rt't'ss. l'lltolof ir,t\ ('lll()\' lrttllt tr,tlt lttttl'
;ilttl rrltsr.t Vitt1, ;,ttrnt;rls I lrr'l' t('( ('t\(' l)tll(' {'lll()\'lll('lll I l(rlll ll rtlr lttttt' ;lllllll,ll.' ,ttttl
RECON NAI SSANCE OBSERVATION
your mind to wander to where it affects Priority I (above) and results in
observer error (Chapter 8).
+ Satisfy basic bodily needs. Plan your sampling periods so that your basic
bodily needs do not suddenly appear to be priority number one; however,
should the urgency of urination and/or delecation prevail, carefully con-
sider the valuable protocols provided by Meyer ( 1989). Meyer has pro-
vided carefully researched recommendations suitable for killer whale
observers in sea kayaks, peregrine falcon observers suspended on a cliff
face, and desert tortoise observers trudging the sands.
Once you have the above priorities firmly established in your research protocol,
remember that periods spent in the field are likely to be some of the most treasured
times of your existence. They should be both productive and enjoyable, but they
won't be constant fun. Lott (197 5) reflected the feelings of many ethologists when he
wrote'Protestations of a field person':
'Welcome back! Have a good vacation?''I wasn't on vacation. I was in
the field.'Well that's not what I mean. Being in the field isn't a vacation;
it's hard work, a hard life, and besides . . . But hold your tongue. People
who spend months at a time noting the behavior of animals in odd
corners of the world are usually greeted that way. We're happy with our
work, of course, but for several reasons it doesn't qualify as a vacation.
Sometimes just living there is a problem. If you can't find or afford
a convenient house, camping out becomes living in a tent by the second
week. And the kind of stick-to-your-ribs food that stores well in a
burlap bag or metal box soon starts to stick in your throat. Some
colleagues and I went to visit Patti Moehlman's burro study in Death
Valley a couple of years ago, and brought along some steak. Patti had
been without refrigeration for weeks. Her response was succinct and
eloquent: 'GOLL-EE REDMEAT.' . . . So welcome was the steak that it
hardly mattered that the water from a desert cloudburst streamed intcr
our plates as we ate crouching under a picnic table.
But food and housing are lar from the worst of it. Your can get used
to eating almost anything and sleeping almost anywhere. The worst ol'
it is that you get to be a little bit batty.
To be more specific, you get to be sort of matnic-deprcssivc. Vrrr
experience mood swings that increase as a direct iunction ol'thc nrrnrbcr'
of seven-day weeks you've spent on the project. . . . Thc rnosl sirlicnt
symptom is that yourevaluattion ol'thc stutly gcls l() bc wiltllv rrrrrcrrlistrt'.
High noon rlay fincl your pulsc rircirtg irs y()ur rrrirrtl lot'rns llrc krrrtl
of- modest. corttitincrl. bul 1'tcttclrirling rcrrrrrks tllrt 1rt'r'surrrlt' llrt'
Nitlitlltitl Acittlctttv ol' St'ie rtt'r.'s l)l('niu v st'ssiort llrlrt llrt' Nolrt'l
('()nlniltt't'tltrl intlcctl knorv tvllrl tl rr';rs tlr)urlr 11 1,r.',, ll ( rl('(l \'oul
HOW TO OBSERVE
analysis of the distribution of deer droppings, the grumpiness of goose
gatherings, or the ballistics of'bison bellowing as the intellectual link
that completed the conceptual chain from molecule to mastodon. Your
lips move a little as you take on a set of bored, cynical journalists who
came to the press conference to play it for laughs and a chance to get in
a dig at the granting agency that spent nearly $1.750 in support of your
research. A basic stock of fine ironic wit, a dash of captivating candor,
an irresistibly lucid illumination of The Link in layman's terms and they
are first sobered, then entranced. When you release them Irom your
spell, they will sprint to their typewriters and set their two forefingers to
banging out near poetry in praise of basic research and (blush) you.
That evening you rnay be so sunk in shame that you want to change
not only your study but your name. How could you have committed
yourself to a study so barren and one for which you are so ill prepared?
What will you say to that granting agency when they ask what became
of more than $ I,750 intended to support significant basic research'l If
you take the entire blame you'll never get another chance. Besides it
wasn't all your fault; but how do you make them understand that fate
has thwarted you at every turn, that your field glasses fogged up during
nearly three goosegatherings, that the rnicrophone salesman was lying,
lying when he told you how far away it would pick up bison bellows'l
Yes, who will bear witness that your failure was not really your fault
now that God has turned his lace lrom you?
And so yoLl go on, ever more sublimely happy, ever nearer suicide.
During your more lucid moments you realize, of course, that you're
getting to be a little bit batty, and you come to crave some stabilizing
influence to dampen your oscillations. Contact with an old friend
becomes so welcome that you hold your tongue even if he says
something stupid like, 'Welcome back! Have a good vacation?'
ISee ulso Huilnnn's ( 1973 ) discussion oJ.fieltli,sm]
The following quotation carries a hidden message: '. . . as the vtork [italics mine]
by Cain and Sheppard has shown . . . '(Tinbergen. 1958). Whether intended or not,
the word work is indicative of what ethological studies can, at times, become. Even
though the overall experience is enjoyable and the results rewarding, it can become
tircsomc. ancl you are often confronted with having to convince yourself that the
cnrl.jrrstilics thc means. Chenev and Seylarth describe the 'syndrome'this way:
Anyonc who has ever studied animals in the natural habitat recognizes
tlurl cvcn tlrc nrost stirlLrlatirrg proiect includes moments of unrelieved
lc'tlitutt. [ ('hcnc.r' und Sciurth. 1990;31 3 J
l'or crlrrrrplt'. l slt's (l')(r7:,15; lrrlrrritlt'rl lo nr';lr lrorctloru wltctt ltc wrotc.'A wcck
llrlt't.lrl () )Ol'Nl .rrltrlt'lulrsottl rrlr)n(', llr('t,rllvtttl'r';tll ol ltvcttrtsltp'rtitttlislt':tctctl
5958 R ECON N A ISSA NCF- OBS E,RVATION
me from the rather tediou.v .joh oJ recorcling gnu ut'tivit,r, putterns [italics mine].'
Schaller's description of part of his study on the Serengeti lion is also illustrative:
My existence revolved around lions, I was wholly saturated with them.
talked and wrote about them, and thought about them. . . . A few times.
though, I saw too much of lions. Once Bill . . . and I decided to track a
lion continuously by radio for several weeks. . . . The first lew days were
rather pleasant. . . . As the days passed this delight vanished, and we
went about our task with grim determination. . . . We stayed with the
male for twenty-one consecutive days and suffice it to say that for
once I had a surfeit of lions. ISclrullcr, 1973:90 9l ]
The descriptions of behavior of wild animals that you read in the literature are
olten the result of weeks. months and years of careful stalking, hiding and
painstaking observations (e.g. Packer, 1994). Often hours are spent in a blind under
less than ideal conditions, with inclement weather making you physically unconr-
lbrtable and your view of the animals poor, and the inactivity of the animals
becomes frustrating. Your binoculars get beaterr about and rained and snowed
Lrpon, and the pages of your field notes become limp and stuck together. Field
research can be trying at times, but you can make the best of it by being physically
and mentally prepared. Expect Murphy's Law. 'If anything can go wrong it will', to
take elfect from time to time. Allow fbr some slack in your schedule to absorb days
when you cannot collect data because of poor weather or equiprnent breakdowns.
Often, you can release much frustration merely by recording the disasters in your
field notes, realizing that in years to come you will remember even those days londly
as you reflect on the data-rich days with pride.
In conclusion. successfui data collection through observations necessitates your:
l. having developecl the skills necessary for ellective and efficient observation (see
exercise below); 2. having the proper equipment (e.g. binoculars and spotting
scopes)l 3. understanding the various ways to describe behavion 4. having a well-
designed system lor recording your field notes; and 5. knowing when your data arc
sufficierrt. The observations we are discussing here are either utl lihitunt saruplcs
(Chapter 8) or initial reconnaissance observations on which ar luture wcll-clcsignerl
study will be based. Regardless. the skills used are the same: only thc rclative crnplt:r-
sis on the data collected is likely to be dillerent.
4.1.2 An exercise in observing
Lcarrt to scc wlrrrt vtltr lrrc Iorlkinu ;rl
l'ir seveltl l,r'rrts Ilrlrrl strrrlllt'tl lo 1111.1 ;ur t'llr'r'lrrr '.ltttlr'ltl',
,t lt,ttt,l
HOW TO OBSERVE,
and I discovered some delightful insights and an eflective method in Frederick
Franck's (1973,1979) books: Tlte Zen o/-Seeing and The Awukened,trl'e. First, I have
to admit that, like Hofitadter (1919:246) '['m not sure I know what Zen is'. But. lor
our purposes, that doesn't matter; Franck's technique of teaching drawing through
seeing is what is irnportant.
While I am SEEING/DRAWING, I take hold of the thing, until it fills
my total capacity lor expcrience. Once I have thus taken possession of a
hill, a body, a flace. I let go, let it go free again, as if I were releasing u
butterfly. Yet it remains mine forever. After much SEEING/DRAWING
my eye goes on drawing whether my hand draws or not.
IFrant'k, 1973.125J
Although Franck developed lris techrrique for teaching drawing through seeing,
I lound it equally effective in teaching seeing/observing through drawing. Based on
Franck's description of his seeing/drawing procedure, I developed the following
cxercise:
' Exercise in devektping observutional skill.s through drutring
. Objective: To develop observational skills, rlot to create an artistic rendi-
tion of the animal. However, it is important to attempt to recreate with
the pencil what you see/observe with your eyes.
Please realize you are not 'making a picture,' yoLI are nol being creative.
We are just conducting an experiment in SEEING, in undivided
attention! Tlie experiment is successful if you sut't'eetl in f-eeling you have
become that leaf or that daisy, regardless of what appears on the paper.
I Frurtck, 1979:rviiJ
' Materials: l. An easily observed animal, perhaps in captivity. It helps if
tlie animal is not overly active. You might find it better to begin with a
stul-tecl aninrarl ancl go frorn Step I to Step 4: then go through the entire
procedure with a lrve animal.
' 2. I'apcr', clipboard and pencil.
' I)nrccrlu rc:
' Ste p: l. l'ind a conrlirrtable place to sit and conduct yourself as an indi-
vitlturl rrlonc u'ith thc i.rnimal. Pay no attention to anything else around
vorr. hcsitlcs tlrc uttinritl.
' .1. SPr'1111 lr li'rv rninrrtcs l'r'ccly obse rvirtg the animal to get'a feel'for its
l'('lr('r ir I llt'lutvirll' llttl tct'lts.
' \ Atsonrt'Poirrt irrtinrc'lrecze'rr rncrttrtlirrrrrgcol'tltcitnintitl:utcl r'lo,rc
tt,ut t tt'r Kt't'gr \'()ur ('\('\r'lost'tl;tntl ltoltl lltt'tttclttrtl iltutgc rrrttil it llrtlcs.
Itt'pt',rlllrr.,rrrrlrlYrrrrr'iurtlr;rrrllr('()ulltttt'.rl lltt':tttitttrtlrrillr\'()tlt('\'('sltott'lo oltst'l\(' ;tlllntill lrr'lutr tot I lrt'rr ..,)lu(' l('n
60 RECONNAISSANCE OBSERVATION
closed; that is, trace the outline of the mental image. It's not important
whether your drawing looks like the animal. Forcing yourself to draw
forces you to form a more stable mental image. Repeat this process until
the mental image is fairly stable and more detailed.
4. Again'freeze'the animal in time and space, but keep your eyes open.
Stare at the space where you'froze'the image and hold it regardless of
what the animal does and where it goes. Repeat this process until you can
hold the image strongly and long enough to draw it while focusing on the
image in space.
Treat your mental image of the animal as the object that Franck is refer-
ring to below:
Allow the image on your retina to set off the reflex arc that goes directly
from your eye, through your body, to the fingers that hold the pencil. . . .
There is no thinking, judging, labeling in this reflex arc: it goes from the
eye to the hand and skips the thinking, judging, discriminating brain:
just allow the reflex to work, to take over! . . . Don't be surprised: in the
beginningyour concentration span will be short. When your attention
flags, stop for a moment. IFrunck, 1979:35,38J
' 5. After you have become reasonably good at Step 4, begin to observe the
animal in motion, first as a series of disjunct'fieeze frames'and then as
continuous motion. Locomotion (e.g. different gaits of horses) provides
an excellent opportunity to develop this skill. At this stage you should be
able to close your eyes and 'replay' a segment with mental images.
' 6. Write a description of a segment of the animal's behavior. Repeat
the process until you see and retain more.
It is most important that you strive to draw in Steps 3 and 4. Just as recopying
class notes helps you retain the information, drawing the animal compels you to
focus your energy into observing and retaining the mental image. This is reflectccl irr
Walther's ( 1984:xi) account of why he draws animals.
I draw animals not to compete with Leonardo da Vinci but to make surc
that I have seen them correctly. As one of my anatomy teachcrs plrnrsccl
it: you have only seen something when you have made a skctch ol'it.
Drawing the animal locuses your attention on its nrorphology. Movcrrrcnls :rntl
posturing result in changes in the relative positions ol'parts ol'thc rrrrirrurl's rrror
phology. Observing the details ol'thc posturcs. rrrrrl thcn llre rrrovcrrrerrts. g.rrtlrr:rllv
becomeseasier. At lirst, yorr will pnrllrrbly ol'rscrvc prinurrrly irr lrlrrt'k lrrrtl w'lrrlt', lrrrt
littcr ytltt will obsct'vc luttl renl('nrl)er t'olor. ('olors ;rntl llrt'rr t'lr;url,('\ ('rn lrt' ;111
itttlloltltttt ttl('irllsol totttnttnu(lrlr()n nr ilntttltls ll tr'tt,trlrtl'tololr r\iln rnl)orl,llrl
HOW TO OBSERVE
part of your research, you should use standards, such as Smithe's ( 1972) 86 standard
colors which are based on Ridgway (1912) and Palmer (1962). After learning to
observe through seeing postures, movements and colors, you can learn to 'observe'
sounds through hearing in a similar manner; sounds should then be incorporated
into your descriptions.
Each step in the exercise outlined above takes time, and Steps 3.4 and 5 will need
to be repeated several times. That time and effort will serve as a good measure of
your disposition and aptitude lor ethological research. If you aren't comfortable
with the concentrated effort required in this exercise, you shouldn't try to conduct
re search that requires extensive observations of an animal's behavior.
For additional exercises in observing you can consult Roth (1982); he offers
scven exercises involving increasingly more difficult activities in a chapter entitled
' I'he art of seeing'.
.{.r.3 Field notes
I iclrl notes are often the best, and sometimes the only, record you have of your
,rt'tivities and observations in the field. The method of taking field notes described
lrt'low is primarily applicable to inlormal field trips and reconnaissance observa-
I r( )r)s. However, for some studies, data can be collected in a field note format which
r r( ( )r'l)ol'rrtes previously designed and prepared data lorms (Chapter 9).
( ioorl lield notes are the end result of developing a skill into an art, and the basis
l, rr lq';srning those skills is a knowledge of fundamentals.
Note taking . . . is an art requiring sensitivity and skill. Perlection is
rrnattarinable, a goal to be sought and pursued through selective training
lnd persistent practice just as beauty or reality are sought by the
sculptor, the musician or the poet. IEmlen, 1958.l7Bl
I lr(' svslcnr ol' taking notes that you decide upon will determine their value to
,,u ,rrrrl olltcr rcscarchers in the future. Most ethologists with whom I have spoken
,r ,{ ',()nr(' vrrt'ilrlion ol'thc system developed by Dr Joseph Grinnell of the Museum
,,1 \r'rlt'lrr:rlc /.oology. IJnivcrsity of California, Berkeley. The usual lormat is to
,lrr r,lt' llrt' Itolclrook ittto tlrree sections: l. journal; 2. species accounts; and 3.
' rt.rl,r1' llrr'specics-lrccotrnts scction is used to keep records of your observations
I , .pr'r t('\, nr t'orttr.;rst ttt thc.iorrrnal. where yilur observations are recorded by date
rrr,lrrrrrr. Ilrt.r'rrtlrlorr,sccliorrisusctl torccordspecimenscollectedinthefield.The
Io lollorv is lr:rsetl rr1'rorr (irinncll's systcm, but will be concerned only
Irrrt'rl prrpr'r slrorrltl lrt'rrsetl. lt slrorrlrl bc rr borrtl, hirving a
Iltt'rtzt'slt,,ttlrl lrc lrltllto\nltill('lV (r' ,irtt'ltes lly li r', irrchcs
62 RECONNAISSANCE OBSERVATION
( l6 centimeters by 2l % centimeters) preferably looseleaf ancl kept in a six- or three-
ring binder. An irnportant reason for a ring binder notebook is that many fielclwork-
ers preler to use two notebooks. One is taken into the field fbr the day's records, and
the other contains past records lor the year and is kept safely in camp or at home.
Some field ethologists prefer to Llse bound notebooks wliich are designed lor
outdoor use, such as durable,45,/t" x 72" notebooks with 80 lined pages and polyeth-
ylene covers, or polyethylene covered ring binders (4t/{' x7") and relatively 'water-
proof' loose leaf paper.
Black waterproof ink is usr,rally recommended; Forestry Suppliers sell a ball-
point pen which will write underwetter, upside down and in temperatures to -50"F
(-45.5"C). A hard pencil is the second best choice. You should always carry a
pencil, however. for both a backup and fbr writing in heavy mist or rain: ink is not
waterproof until it is dry. If you r-rse a Rapidograph pen, try to use a 'noncloggir-rg'
drawing ink. The lollowing three inks are recommended: l. Pelikan Drawing Ink; 2.
Higgins Eternal Black Ink; and 3. Koh-l-Noor Rapidograph lnk.
A sarnple field note (journal) page is shown in Box 4.1.
Box 4.1 The field note journal
A sample field note (journal) page is shown below:
Page no.
Name
Locality
Date
Beginning mileage
Mileage at stop points
Other observers
Weather
Habitat type
Time into field
Time: Observations and remarks
Time: Observations and remarks
T'itnc otrl ol'licltl
I :tttlirty' ntt lt'1r1,1'
HOW TO OBSERVE
Box 4.1 (cont.)
Lot'ulity'. Specific locality, clirection and estimatecl distance frot.t.t
known point (e.9. E shore of Cobb Lake, 6 km NE of Ft. Collins,
Colorado); section, township and range are also useful inlornration.
Dutt': Date of observations. travel, meetings, etc.
Miltuge (beginning, stop points, untl entlinS4):This provides a record to
confirm route of travel and may later provide useful additional
inlbrmation when giving directions to others (or conferring with the
rRS).
Othcr observcrs'. Provides for later verilication and elaboration
(Remsen, 1971).
Ll'euther: Precipitatiorl, percent cloud cover, wind speed anci direction,
temperature, etc. Insert cltunges in yp71v ttoles us tlrcy o('('ur.
Temperature can be measured by carrying a small. metal-shielded
thermometer with you into the lield. For most str.rdies it will be
sufficient, anc'l worthwhile (e.g. Mrosovsky and Shettleworth. 1915),
to estimate measLlres of the other weather variables. tn 1805.
Commander Francis Beaufbrt of the British Navy devised a scale of
nine categories ltrr classifying wincl lorce at sezi. More recently a
scale was developed (based on Beaufbrt's scale ) tbr use on land. The
scale's l3 categories are convenient for cstirnutiri,r; wind speed while
in tlie field:
Butu.fbrt',t ,stult'.f or vind ,speed
Scale Wind velocitv Environmental indicators
0 (.ultrt Movement of the air is less than I mile
(1.6 km) per hour. Smoke rises vertically;
bodies of water are mirror-srnooth.
I l,ichr uir I 3 miles ( 1.6-4.8 kn"r) per hour. The drift of
smoke indicates the direction of the breeze.
) l.i,qltt ltn,c:t, 4 7 n-riles (6.4 11.3 km) per hour. Leaves
begin to rustle.
\ (it'tttlt' ltn,t:t, 8 l2 niiles (12.9 19.3 kni) per hour. Leaves
lrnrl twigs in urotion: crests on waves begin
lo hrclrk.
I l lrtrlt't'tttt'l,tt't'.,' I I ll"i (-ltl.',t l() 0 ktn)1tct'Itottr. SntitIl
lrr :rrrr'lrr's nl()\'(': tlrrst r ises: nlllnV rvltitcc:r1-ls
ott l;ttI't' lr,rtltr"'rrl rtltlt't
63
R ECON NA I SSANCE OBSERVATION HOW TO OBSERVE
Route of travel
Hours of observation Weather
Species observed
General impressions about the day's observations
Some fieldworkers recopy their field notes after a day's observations (e.g., Schaller,
1973; Remsen, 1977; P. Johnsgard, pers. commun.). Others believe that your first
impressions are the most accurate and that in recopying you are prone to edit them,
therebymakingthemlessaccurate. Pastjournalsshould bekeptbyyear. Field notesare
extremelyvaluable, and loss ordestruction in thefield, home orofficemust be avoided.
Regardless of how you choose to take and store your field notes, remember that
they are a record of your fieldwork - be c'omplete. They are a source of data and
hypotheses and can be the basis for future research be accurate. They may be used
by other researchers for similar purposes - be c'lear and concise. Last, but not least,
your field notes will be a diary and a source of memories; insert thoughts you will
cnjoy having again,2O or40 years later.
4.t.4 Equipment
'l-his section will deal with the three basic tools used in field ethology. More sophisti-
cirted, high-tech data collection and analysis equipment will be discussed in
('lrapters 9 and 13-17, but lor reconnaissance observations and some descriptive
studies a blind, binoculars and a field notebook will often suffice. Huxley's
(1968:15.76) account of his classic study in 1914 could easily be used to recount a
tlcscriptive study of today.
A good glass, lbinocularsl a notebook, some patience, and a spare
fortnight in the spring - with these I not only managed to discover many
unknown lacts about the crested grebe, but also had one of the
pleasantest of holidays. . . . Some of the watching was done concealed in
the boat-houses, and some from a screened punt, but the major part
ll'orn the bank. This in many ways the most useful . . . every action can
bc casily krllowed, the birds are not scared, the field of view is
rrrrirrte rruptccl, and it is far easier to follow the actions of the same pair
ol'bircls lirr':r long pcriod of time.
.t. t..tu lllinls
llrt'prnposcol ;r lrlrrrtl 1or lrrtlc)islo:rllorvobscrvlrlionol'itttitnitlswithaslittledis-
lrrr lrlut( (' ;t\ Possrlrlt' (t' ,' Sr)r('nsott. l()().1) I lr:rl is. y,ltt ltrlpc yrltt :tt'c obsct'viltg
Irt'lt.trlot \\ll( lr l:. ult.rllt't lr'tl l11 yottt l)r('\('n(('. t'\r'tl tl V()tlt l)t('s('tt('r'ts Pett't'ivctl lry
65
Box 4.1 (cont.')
5 Fresh hreeze
6 Strong breeze
19-24 miles (30.6-38.6 km) per hour. Small
trees in leaf begin to sway.
25 3l miles (40.249.9 km) per hour. Large
branches begin moving.
32-38 miles (51.5-61.1 km) per hour. Whole
trees in motion.
3946 miles (62.8-14.0 km) per hour. Twigs
on trees break off.
47-54 miles (75.6 86.9 km) per hour. Foam
blows in dense streaks across water at sea.
55-63 miles (88.5-101.4 km) per hour. Trees
uprooted; huge waves build up with
overhanging crests.
64-75 miles (103.0-120.7 km) per hour.
Wind velocities above 75 miles (120.7 km)
per hour.
l0
l1
12
Moderate gale
Fresh gale
Strong gale
Whole gale
Storm
Hurricane
If you need accurate (+3"1') measures of wind velocity, small hand-held,
digital anemometers which read in three scales (fpm, m/s, mph, and knots) are
available for example from Cole-Palmer Instrument Co., 7425 North Oak Park
Ave., Chicago, Illinois 60648.
Habitat type: General topography and vegetative cover; note
prominent physiographic features.
Time into .field: Time at which you begin your fleld-related activities
(e.g. 1345-1510). Midnight:0000; Noon: 1200; 6:00 pm: 1800.
Ohservations and remarks'.
1 Record the species, number, age, and sexes if possible.
2 Describe behavior as accurately, clearly, concisely, and completely as
possible (see discussion below).
3 Include remarks such as unusual occurrences (Short, 1970), thoughts.
and ideas about the behavior. Lindauer (1985:7) reports that Karl vorr
Frisch'had a weakness for little things. for unexpected rcsults. lirr so
called singularities' .
Record observations at on('e tkt nol lrusl lo nt(nt()r.t'.
Time oul o/'liekl: It is clcsirablc to rccorrl tirnc rrt wlrrclr yorr lr';rvt'llrr'
sturly sitc. lrs wcll irs whcrr yrrtr rcirclr Ir0rrre ()r'r'iuill).
(itttt'r:tl ('t)tntnt'nl.\". At tlrt't'ntl ol t';tt'lt rl;tv's ltt'lrl olrst'tr;rlrotrs rl ts
rrllt'tt rlt'sit;tlllt'lo ltr'rtrl:r tt('\\'rlt1't'( ir'ttt'trtl ('o1111111'111 r;tttrl lt'.1
6766 R ECON NAISSANC E OBSERVATION
the animals. In situations where animals are accustomed to hur-nan presence. or
where you can habituate them to yourself, no blind is necessary. At the other
extreme are species with whom great caution must be employed. You can think of
too much activity in the field as having the lollowing effect:
A walker displaces the territory as a swimmer does water, but a quiet
sitter is a dropped stone and his ripples subside and water laps back in:
submergence. [Haut-Moon, l99l;-]67J
Illinds are of two general types natural and artificial and may be in. on or
beside water; or they n-ray be below, at or above ground level. Knowledge of the
animal's reactions to novel objects at various places in their environrnent is neces-
sary lor selecting the proper blincJ. For example. sitting in a tree will sulficiently hide
yc.ru from many species that are not prone to be look vigilantly tzrr above ground
level(e.g. deer).
Artificial blincls are generally designed to blend in with the habitat as closely as
possible. An unobtrusive blind is less likely to disturb the animals and attract
curious humans. However, rarther than selecting a natural blind (or constructing an
artificial blind) with as little disturbance as possible, you might be able to use an
obviours structure (e.g. vehicle, tent) and allow the animals time to habituate to it.
For example. since coyotes in the National Eik Refuge were accustomed to seeing
vehicles along the dirt roads. Ryden (1975) rented a bright yellow van to use as a
blind lor her observations. The same ploy was used by Kucera ( 1978) in his study of
mule deer in Big Bend National Park. by Walther ( 1978) in his observations of oryx
in Serengeti National Park. by Renouf (1989) in his str.rdy of harbor seals. ancl by
Laurenson and Caro (1994) in their study of cheetahs. Even with domestic animals,
similar procedures are often necessary to ensure that the animals under observatiorr
are not clisturbecl by the researcher's presence. For exermple. Baldock ct ul. (1988)
described their use of the same technique in their stucly of domestic sheep:
All observations of behaviour were made from a parked vehicle
overlooking the fielcl containing the ewes. Other vehicles were rcgularly
parkecl nearby: We obtained access discreetly ancl quietly. nrukirrg cvcrv
ef-fort not to disturb the sheep. As far as we could tell. thc hchaviorrr ol'
the sheep was not affbcted by the observer's presencc.
f I)ultlttt A, ct ill /(/,\,\ i/)/
Nylon or canvas tents clfien make goocl urtificial blinds. Snrirll. liglrtw'ciplrt tt'rrts
can easily be movecl between obscrvatiott sitcs. irntl lirrgcr tcrrls clrrr lre stlrketl intrr
the grottncl to prtlviclc ir ntorc pcnniurcnl blirrrl. Il'yort rlct'rtlc to lrrrrltl rr lrlirrtl. llrcrt'
itrc scvct'ltl soutccs ol'irtsttur'liolts lir lrrriltlinl r"rriorrs l\ l)('\. ir\ rrt'll .rs rrlt';rs lor t rl
rtlilt! votil ()\\'rl rlt'sit'n. l ot r'rlrrrt;llt'. \\oorlur (l()S \) rlt",t rllrt'r t,rtr'.lrut lron ,rl ,l
Potl;rlrlr'rrtttlrtr'll;r lrlrtrrl ;rtttl l{,,.1r'nlrou',('iut(l llt'.,l 1lt)li \)rlt',,t llrt'r on',lut( lrrrrl ol
,r l)()tl,rlrlt'lr'\\r'r lrl||r(l l tt,ttt, l l rllrr',lt,rl, , lltr'rlr".r1'rr rrl lrr| 11|r",,,1 lrlrtrrl
HOW TO OBSERVE
lrig.,1.l lrxumples ol observation blinds (fiom Pettingill 1970).
'fhc lirllowing charactcristics shor-rlcl be considered when selecting a uatural
blinrl or conslructing irn artificialblind:
t llclrlrvior-ol'irttintitl
ir. l{crrctiorr to str'rrngc ob.jccts. itpproach or avoidJ
lr SP;llirrl rlistribtrlion ol'bchltviorpitltcrns: ure you at the right spot to
, rlrsr't vr' I I ri' lrt'lt;tr,' irlt''.)
' ( )lr.,r'r \;tl toll;tl t lrlr;rllrlrll
,r Nrrrrrlrr'r tut(l \r./('()l ()l)('nttt1's lot olrst'lvllliott lttttl lilrrrrrrp
Ir ( ,r1r.tr tl\ l,)l lttltttlrt'l oI ,rlr',t'l t('l', illlltt tlrltlt'tI
t lrr'llll,llt( lt( r'
R ECON NA I SSANCE OBSERVATION
Can it be permanent fbr several weeks or years'l Will the animals be
there during your observation periods?
Should the blind be temporary and portable (e.g. Winkler, 1994)? How
olten and how rapid will the moves be? A camouflage suit can be con-
sidered the most easily and rapidly moved artificial blind.
+ Climatic conditions
a. Severity; must it be built to withstand severe wind and precipitation?
b. Prevailing winds may be important for locating the blind downwind
to reduce your olfactory and auditory stimuli from reaching the
animals.
c. Comlort and portability are often conflicting objectives. Rernember
that you can function effectively as an observer/recorder only if you
are rea sonably conr lortable.
Further descriptions and discussions of blinds and their use can be found in
Hanenkrat (1977), Roth (1982) and outdoor photography literature, such as Baufle
and Varin (1972). Ettlinger (1914), and Marchington and Clay (1914).
4.t.4h Binoculars and spotting scopes
Binoc'ulars
One of the most important pieces of equipment to the ethologist is a good pair of
binoculars.Infact, asTinbergen( 1953:132)has said, they'. . . arealmost indispensable'
Humans are a visually oriented species; therefore, ethologists tend to rely very
heavily on what they see. A very large percentage (probably over 95'Yu) of what we
record as observations are what we see. Equipment that will provide us with better
vision or in other ways make the animals more visible, such as a strategically located
blind, will pay off immensely. Always consider the species to be studied and the dis-
tances over which they will be observed when selecting binoculars or spotting
scopes (see below).
Bergman (1981) has listed several criteria for evaluating the optical qLrality ol'
binoculars, including the fbllowing:
t Brightnes,r of the image (see below for a measure of relartivc brightncss).
2 Resolution of the image which can be affected by the firllowing tlcll'cts.
a. Edge-of-field de/bcLr. The margirts of the ficlcl ol'vicw shorrlrl rr1'rprirri-
mate the sharpness of the center.
b. Pintushitn tli,slorliol. Pitt'ltllcl littcs ctrrssirrlt tlrc licltl ol vicw rrrrv
ilppcill't() cul'vc lowlrrtl lltc ccrrte r'.
c.('ttrrttlttt't'ttf lltt'ittttt.r,r'. Asllti,'ltl surllrt'r'.srrtlr ;rr;r rr:rllln;t\;tl)l)(.iu
('()ll('ll\'(' ()l ('( )ll\ ('\
a.
HOW TO OBSERVE
d. Splrcric'al oberrotion Results in the inability to foous the binoculars
sharply.
t Range of resolution. Good optics should have a wide range of distance
over which they are in focus.
+ Alignment.The images seen through each barrel of the binocular should
align and merge perlectly into a single image.
s Eye relieJ'. When the binoculars are held comfortably to the eyes, you
should see a full field of view. Eyeglass wearers should check the effect of
the retractable cups found on many binoculars.
There are two numbers engraved on all binoculars. These are commonly used to
designate the'type'of binoculars, such as'7 by 35':
7x35
magnification diameter of objective lens (mm)
Mugnific'atiorr tells you the number of times greater than normal that an object
being viewed will appear. Although increased magnification would appear to be
tlesirable, it often carries with it some problems. Generally, the following occurs
with increased magnification:
t The field of view becomes smaller (see below).
z Clarity is lost, since the more powerful the lens the more the imperfec-
tions in the lens are also magnified.
I Light transmission is decreased.
+ Increased blurring results from movement of the binoculars.
-Ihe first three problems can, of course, be overcome by the manufacturer, but
tlris rvill result in higher-priced binoculars. For most field studies,6 to 8x magnifica-
tron will probably be sufficient. When greater magnification is necessary, spotting
\('()l)c:i rrre commonly used (discussed later). However, Huxley (1968) used l2x
lrrrroctrlars in his classic stucly in 1914 of the courtship behaviors of great crested
l,rt'lrcs ll\ttlicrlt,s rri,stulus\, even though the optics at that time were not nearly as
lootl irs thcy arc toclay. Flegg (1972) can be consulted for recommendations on the
I r'pt' ol. binoculars (mag. x clbjective lens diameter) to be used for observing birds in
tlrllt're rrt light lcvcls ancl lrabitat types, and over different distances.
()ltjt't tir'<' lt'rr.s' tlitutrt,tcl irll'ects the amount of light that enters the binocular.
\\ lr;rl is irrrporlrrrrl. lrowcvcr. is thc amor-rnt ol light which finally passes through the
.t ulirr lt'rrs (lillrl lnrrrsrnissiorr or rclativc brightncss). Everything else being equal,
tlrr'l;ul,t'r llrr'olrjt't'livc lerrs lltc gt'clrlcr tltc rcllrlivc hrightncss: tlrcrctitrc. binoculars
rrrllrl;rr,'t'olrlcr'lrvt'lt'ns;ut'llt'llt'r ttntlt't lorvlilltl t'otttlitirltts(c.g.tlttwtt.tlrrsk).Ttl
t onrli,ur'1t1,111 lr:ur\nr\\rorr lot trrt o,rlt'tl lrtttor'ttl:tt\ u\('lltt'lirllolvtttlt, lilt tttttllt:
!
an
a
z
z
a
a
z
a
an
a
rn
I-
z
=?lt+i*ei;s 
.15:Ei:gir ii?r3i: Iu':i ?=iZ =-=Z'i- =+ t=ir+,; fr , r-i_-==Ea;: -=;! vliniSrs+ig1 iii; Eaiie: i ;-ia;"lE,-+!
z=V": Bli;A g a -a "q1 .7ao 
J! 'a 2..?ae =z - -.r .i122;EIir#;= € =,aa:rr3r- F +Ei+EF-* 6 E
,zztr grEiE; Aitizii*Ei a ,Ziti F-"i?u
!-'==i;1if:Ea -: aEi ;i;gl cr :eA[aE [''q-z777ii*i'Fi E* ii: s=ae.E: x= tAci;s- * A
=?if i,Zi?i; E e aE i s,gE s iE i 
* 
e;E- EE lEA
=Zl=, ;E;EfE -.: oq!.7 :r-sqQE,E" =d; ==' ;S:-=22 :i:;"ad E+ i=i egrE=A:a Aia E3 331
t=.1t= 
=;g+gg 
ia Ii?gt1;1=i aiE g1 i=?-== =: 7Zr;sz-=" = gg 4=7.;l sr-i. s3 4 =:;1=7 aiZl'tE i ; o 1*g{; i=i xi +'- . : = =.= = - '- = ; a d ?. * a..E -= = = oe
=7i=_ 
i7=z=,=" ii ?'=iii, EZi ?', E^==:1. ;i='-!z i- ia;El EEa ;i V=-12.= i".i7;Zi Ea Aig+i \E; EE -,'
===a 
:-2'.;i; i: geaEE. fng -=H A
T.,:.: J.I. 5rrnt, spetiftt'utiorts for representative binoc'ulars
\l . ;el
Diameter
eut pupil
(mtn )
Relative
brightness 1001,
Field (at
1000 Yds)
Field
(angular
degrees)
Relative
fleld (lt)
Relative light elflciency (RLE)
Percentage of coating
)0"/,, 80"1,
..r1,/i r .tttttttlunl ltc'll
^, 1-{
_.U
- ls
- 
-:5
- jrt
. lr)
2.5
5
2.6
5
7.1
3.15
6.2
25
6.8
6.8
21
1.5
26.5
55
15.5
21.5
15.5
15,5
27.5
21.5
8.7
35
9.5
35
70
20
22
31.5
37.5
75
26.2
31.5
2l
2t
31.5
23
37.5
370
450
325
380
380
330
636
511
525
390
450
315
390
310
l
8.5
6.2
7.3
7.3
6.3
t2
1l
t0
1.4
8.5
7.2
1.4
7
2220
2700
2275
2660
2660
2640
3816
3462
3675
3 120
3600
3000
3510
3700
25
50
14
3 ' ,, ulur.\ .yemi-tt'ide .field und wide field
-,1+
n , l-i
- ' -1,i
: . -1tt
i .:30
S'rl0
9 < 15
I rt ..r _50
4t6
4.2 11.5
525
3.15 t4
3.15 t4
525
35
20
20
35
2t
35
3.9
5
l5
25
\,,111'1'r': From Reichert and Reichert (1961).
R ECON NAISSANCE OBSERVATION
yards (900 meters); that is, the width of the scene you can see at 1000 yards (900
meters). The field of view is controlled primarily by the field lens. The normal field of
view can be increased (semi-wide or wide field) by the manufacturer by using a differ-
ent ocular system, especially a larger field lens. This. of course, also increases the
price of binoculars. The following formula converts field of view in degrees (Table
4. I ) to an approximation of field of view in leet at I 000 yards (Robinson, 1 989).
Field of view:Field of view (degrees)x53 (ft at 1000 yds)
Generally, the greater the magnification the smaller the field of view. Reichert
and Reichert (1961) provide a formula to calculate the relative field for diflerent
types of binoculars.
Relative field:magnificationXfield at 1000 yards
The larger the relative field, the closer the binocular approaches the ideal (i.e.high
magnification and large field of view).
Binocular locusing systems are of two types. With individual eyepiece focus the
observer locuses each eyepiece separately while keeping the other eye closed. If you
focus them while viewing a distant object, your binoculars will be in focus at all dis-
tances beyond about 30 feet (9.1 meters). You must refocus for closer objects.
Binoculars constructed with individual eyepiece focus are generally better sealed
against moisture and dirt than are center focusing binoculars.
When adjusting center focus binoculars the observer uses the center focus wheel
to focus the left eyepiece while the right eye is closed, and then the right eyepiece is
focused while the lelt eye is closed. Now the observer can focus the binoculars fbr
varying distances by using the center focus alone. This is an advantage over individ-
ual eyepiece focus binoculars.
It should be clear from this overview of binoculars that the choice of tlie proper
binocular is always going to be a trade-off of advantageous and disadvantageous
characteristics. These are summarized in Table 4.2.
An advance in prism binoculars has been the development of roof-prisrns. Lcitz
was the first to introduce roof-prism binoculars, and they still produce high-rluality
optical instruments. The optical characteristics of roof-prism binoculars, altlrorrglr
essentially the same as those lor porro-prism binoculars, are in s()rne irrstirnccs
better. Representative figures are given in Table 4.3.
The greatest advantages of roof-prism binoculars arc thcir clrse ol'luurrllirrl,
and light weight, which result from their slim shapc anrl snurll sizc conrplrr.t'tl lo
porro-prism binoculars. IJltra-crlnrpitcl nrol'-1'l'isrn birrot'rrlrrr s lr;rvt' lrt't ornt'
popular with tniuty licltl cthologisls ttow llr:rl tlrerr oplit';rlt'lr;rrrr'lcrislics;u('('()nr
pitt'ltblc lo l:u'gct'. lreltvit't' tttotlr'ls (llrllle .l .l) llrt' u't'i1'111 ,rl rrllrir ('onlp:r( l rool
pt'isttt hittrlr'ttl:us ('iur lrt' otrl\' |\ .)\",, lllrl ol r'orrrP;rr;rlrlr' ',l,rrrrl,rrrl ',r.zt'rl
lrttt,tr'ttlttt'. l(rtol grt t',ttt l,tn,,t ltl,u',,1t('nlr)t('('\lrt'tr',ttt'llr.ur Ir)lu lrr',rrr lrnr,,, ll
HOW TO OBSERVE
Table 4.2. Sumntary d aclvantages uncl disadvantoges that uccrue from /batures in
birutcular,s
Features Advantages Disadvantages
1. Greater
magnification
2. Larger objective
lens
3. Larger field of view
4. Coating
5. Individual
eyepiece focus
6. Center focus
7. Rubber'armored'
covering
Viewing animals more
closely
More light transmissron
lncreased size of scene
Increased light transmission
Better sealing against
moisture and dirt
Use of center locus alone
for varying distances
Better withstands'hard' use
Less reflection of light
Smaller field of view
Lower light transmission
Poorer image clarity
Increased movement of
binoculars
Greater weight
Heavier
lncreased price
Increased price
Individual focus of
eyepieces at close
distance
Less well sealed against
moisture and dirt
Inceased price
frtble 4.3. Some representative optical specific'ution.s.f or roof -prism hinoculars
Diameter exit
Model pupil (mm)
Field (at
Relative 1000 yds)
brightness (ft(m))
Field
(Angular Relative
degrees field (ft(mm))
6x l8
7x2l
lix24
-1
3
9
9
9
420 (128)
372 (tt3)
366 (l I l)
2s20 (768)
2604 (7e4)
2e28 (892)
8
7.6
7
lrtt's. brrl only tlrc inrliviclual consumer can properly weigh differences in leatures
\ ('r'sus tlrc rlilli'r'crrccs ilr cost.
llittot'ttlrt t's tlurt clcct r ort icirlly zoonr (c.g. Copitrtr z-ooll frr>rn 7 X to l 5 X ) are avail-
,tlrlt' ltottt rt lt'tt' rlistrtbrrlot's, lrowcvcr', tlrcsc birrocrrllrrs prrlbirbly hirve pottrcr optical
tllttrttlt'ttsltcsllt;ttttttosl r'lltolo;'j51suill litrtllrt't't';lt:rlllt'lilrlotrt-lcrnrrlltsct'vilti()lls.
Itr,,1,.rorl tlrrt rrsst()n\ ()l lltr';'1'1,.',,r1 t lt;rtltt'lt.urltt's ol lttnrlt'ttl;tts lt|trl lltr.it rtsr.
.lilt 11,';,1ttilrl't,rrrlr,'1,)utr(lttlllr't1,nl,ilt(l'))il),trrrll(trllilt.,(ril(l()fi())
T.rble 1.1. Sontc representutive spec'it'icution,s Jrtr ultra-light rorf-prisnt binot'ulurs (/t(nt) )
Weight
(oz.(g))
Field
(dee.)
Field
(at 1000
Yds)
Eye
relief
(mm)
Near
focus
(ft(m))
Exit
pupil
(mm)
Relative
brightness
index
.'.1-i Celestron WA Monocular
.r:t t Pentor Mono/Micro
-r.lr t Pentax MonoiMicro
^rluB Zerss Monocular
. rl I Oritrn Super Compact
. rl5 Onon Super Compact
.'.15 Ceiestron WA Mini
-r-,, Pentitr Compact
*il', P:nt;.rr Conlpact
.r.' r \ikt'rn Sprtrtstar
..'.1 - C'elestrr)n \\'aterproof
.,.1 ,B 5qi.i1'lrrski Habicht
. -.1-<B Zeiss \lini
4 (113.4)
6(170.1)
2.5 (70.8)
1.7 (48.2)
6(170.1)
9 (2ss.l )
l0 (280.3)
1 .4 (209.8)
1 .4 (209.8)
7.5 (212.6\
t4 (396.9)
1.6 (2ts.s)
1.5 (212.6)
8.7
6.2
1.5
6.9
7.0
5.5
8.7
1.5
6.2
6.3
6.0
6.6
5.4
4s6 (t3e)
32s (99)
393 (120)
362 (l l0)
368 (l l2)
289 (88)
451 (t3e)
394 (120)
326 (99)
331 ( l0l )
315 (e6)
346 (l0s)
284 (86)
5
l0
ll
l5
l0
9
5
t2
t2
l0
l5
l3
t4
l5 (4.s)
6 (l.8)
l 1 (3.3)
6.6 (2.0)
13 (3.9)
l s (4.s)
l5 (4.s)
8 (2.4)
8 (2.4)
e (2.1)
l8 (5.s)
13 (3.9)
l8 (5.s)
3.1
3.1
2.8
J.J
2.6
2.5
3.1
2.9
2.2
2.5
2.6
2.5
2.5
9.8
14.0
8.2
ll.l
6.9
6.3
9.8
8.2
4.9
6.3
6.9
6.3
6.3
!
V)
an
rn
(D
a
0a
.D
t
tl
o=CDFj
vtX
.D3OE
o
o-
ou)
c,h O
d(:D
o?
oa5
)c.
qe
o
oa
(DD
U)
a-1
.D=op
+X
cD3
IC
5 -a'
+o:
o7.
(-(D
e{(D5
.)
rDx
tJ =Or>
NJ)oo-
a
()
ia
<J
. = _,-t;=i?. i_ 1E 
== 
I.?E ! =; U_.; -18 7 =;? r i 3E e 
g; -; 
=; E1_?'r-i=>Eti3f 47;=+=5 F =-a =-=-1 ;2'ivi*Ai=i-?iii L =ia, 
=7;_7i=X2j;3 : ?ii= =E 5 i;7=2.===??:1 3,a:;=qaEE 1 e'=l
= =_: 1 Va n == 
4 e i I E 7 g r lE i : =__!
?a zZit :i JEZ iiVE 4r :f :]E F ii^.-JJiia='O!'.=?;Ftniff:iE;i=-ii.E= r- if 11=-i;q?5! 
=3Li',Iii=7i 
; ?'ii
=:ilao: t=l A;.Ev..aJ! ={E=?.=5I=d qei--27t2= t q 7i qr r=7 F 3=;
==7:u +; T g2 a7 qi =6 
,Ja:'=21{ef3 iiE;;+i 74 ;s'-=E??=Z t' j'7L=gV i? 7='+= == ;! i i ?;? =, i i5 2=:1;alil =ciiie; ?? €I=:1=-;?i ;EsItEi EE t,=-=1*aEi iLiGZ,1: =i \+=;1?=t;t i::S1=1 e= n?=?i+=.E? Ev=:EIu P+ =E7?; == 1; 31ift?i3- =E- ?i:=;L* =t a aa;:? r G E-7Z *r, + ? i Xia: a; { ii €B \)
--;-::r:::*
!
an-
l,
z
z
a
(n
z
o
Fl
c
a
-l
z
?a9
S.DSsRi-
i' tn
rt;4
^ 
.J<\
.is-r a:
3
\:.
a:
ras
%%
-\
(\
a-
7
oq
o
d
(D
a
oc
.D:1
SurN)
XXX
N) t.JNJO@
T-,^.: J.6. .\rttnt, spet'ific'uti\ns for represenative spotting scopes
\ { t -'\l -:,
Diameter
erit pupil
(ntml
Relative
brightness 100"/,
Field (at
1000 yds)
ltttm))
Relative light efficiency (RLE)
Percentage of coating
Field
(angular Relative
20,,/" 80u/', degrees) field (ft(m))
_ ,-1, r
_- ,-<rt
_ ' j',
.-t'fr r
- br t
: . h( I
: 'ftt t
- ,. 6{)
4
9.6
6.2
l6
9
9
4
2.2
4.5
1
n.5
l0
4.5
2.4
5.6
8.8
22.5
12.5
5.6
3.1
6
14.5
9.4
24
13.5
13.5
6
11
J. _1
2
3.1
2.5
tjt (32.6)
200 (60.9)
l 18 (3s.9)
150 (4s.1)
n2 (34.1)
170 (s1.8)
80 (24.3)
6l (18.5)
2140 (6s2.2)
3200 (97s.3)
2360 (719.3)
22s0 (685.8)
2240 (682.1)
3400 (1036.3)
2400 (73t.s)
2440 (743.7)
2.1
3.8
2.3
J
2.1
J. -'
1.5
1.2
1
J
a
-1
2
1.5
\ ,1;.r'. From Reichert and Reichert (1961).
78 R ECON N AISSAN C E OBSERVATION
Fig. 4.2 Andy Sancloval observing bighorn sheep through a spotting scope mouuted 
on a
gunstock.
L/ i e lr i n g i ns t r ul nu t t s .fil r n o t' t ttr ttu l t l b st, rl, u t i ( )11 S
Night vision binoculars were developed by the US Department of Defense and tile
Soviet Union in the lg60s fbr military use uncler conditions of extremely low 
light
levels. The technology has irnproved from Generation 0' which required 
au infrared
light source. to Generation II, with improverJ photo-intensifiercapacity and 
decreasecl
size. Generation II is available tbr civilian use. but Generation I I I. which uses a 
sLlper-
selsitive photocathode, is only available to military and government agencies'
These binoculars photomultiply the available light by approximately 30(xx)x'
but they magnify the image only approximately 2.5x. TheRussian tccl.tnology
binoculars are available commercially from a lew manufacturers antl clistrihrt(ol's'
such as Damark (7101 winnetka Ave. N., PO Box 299(X). Mittttcitl'rolis" MN
55429 0900). The prirnary American technology binocttlars arc l'l"l"s Nielrt
Mari,er ancl Bausch ancl Lomb's Night Ranger 250: both thesc hittoctttrt|s rvctt'
developed by ITT. The American technology provicles bettcr Iicltl ttl' vicr" 
('10
versLlS 10"). waterprtltll constt'ttctiotl' httoyittrcy. lighlwcighl lrlrtl hlil'lrl \()tll( 
('
prtttcetirtl (Arrer.rvrnotrs. l()()5). Atlrlitiorrll ittlirt'ttttttioll cllll Irc oh(rrtttt'tl itttttt
llttlst'lt & I ,rtttlr
Spotl', ( )pltt r I)tr t'-totl
(l r(l(l( orl\
()rrrl.rrr,ll',ttl' h'rlr(,'l I I 
"\
HOW TO OBSERVE
ITT Night Vision
7635 Plantation Rd.
Roanoke. YA24091. USA
Night vision monoculars and binoculars are sold commercially by numerous out-
doors sporting equipment dealers.
Night vision scopes were developed along with binoculars. They photomultiply
the environmentalillumination by 20 000-50 000 x and have proved uselul for noctur-
nal observations (e.g. Clapperton, 1989; Waser, 1975a). Bausch and Lomb's Night
Ranger 150 (developed by ITT; can be fitted with a 3-in- I rnagnification lens which
extends the normal 2.2x magnification to 6 x . Additional specifications and ordering
infbrmation can be obtained from the sources listed above. Also. Noctron Electronics
and Javelin Electronics (6357 Arizona Circle, Los Angeles, Calilornia 90045)manu-
lacture starlight scopes which are relatively small and practical lor ethological obser-
vations (e.g. Randall, 1994). They are available in dilferent models which vary ilr
physicaldimensions. light arnplification, and magnification and have options for use
with stilland motion-picture cameras. as wellas video recorders. An excellent review
of instruments for nocturnal observations is provided by Hill and Clayton ( 1985).
Infrared viewing devices can also be used lor nocturnal observations. They flood
iln area with infrared light, and an infrared sensitive scope is used to view the area
itnd observe the animals'behavior (Figure 4.3)
Night vision equiprnent can olten be obtained on loan from the US Army and
Navy. Inquiries should be directed to:
Army Technology Transler Program
N ight Vision Directorate
ATTN AMSEL RD NV TSD PET (Miller)
10221 Burbeck Ste 430
Ft. Belvoir. VA 22060 5806, USA
Naval Air Warfare Center Weapons Division
Measurements and Support Systems Branch (Code P2391)
Point Mugu, C A93042-5001. USA
I I i.t t c I I t t t t t' r t t t,: t t I t,t' t' t' r' t t I i t t t t t t I t I c y i t L'.t
Sr'rcr lrl tyPcs ol'sPccilrl rttiscclllrncous obscl'vittiortal tlcvices ltave been developed by
rrrrliritlrrrl rt'st'lrlt'lrt'rs to rnr't't tlrr'ir pirrtierrllrr rrcctls. l'ir crlttnl'tlc. I)itrkcr'(1972)
,rnrl Sttrtllr rrrtrl Sllt'rrt't't (l()'/6) rlt'rt'loPr'tl ntirol rurtl Poli'tlt'r,'ir'cs ulriclt lrllowcrl
lltt'ttt tt, lr't'1. tttlo 1111'lr lrttrlr' trt'sl: l\ltrl;rrtl\ ;rrrrl Nlr('orttlr (l()S.))(l('\t'lrlllq'1 1 ;q
Itl,,'t ,r;rltr',',\',lr'tttlt,t ,rlr',t't\illl,illltt'r'(,t\tlt(", l)t",till)ltrrtt',trl t,ilttr11'..1.'tl(('\iil('
'.r',tllt l,,l llrrotll'lt('ttl lltr'lr'r ltttt,.tl.tttrl Io1,rrl,rt ltl('t,lllrr, l lo\\{ \r't lttttr'r,llt rrll('tl
lrt lr, lt, t ,1r, ttl ,t1'ltlf tttl' \{rlll rr\\ ll lll)'r'llllll\ 1,, ,lr \i l'rl}tll}' ,l rlr'\ lr r' lil ltlr'r'l \{rlll
19
i
lL
I
1
80 R ECON N AISSANCE OBSERVATION
Linda Pezzolesi and the infrarerJ night scope slte usetl ttl tlbscrvc 
bttt'rowittpr t'ul
behavior (Photo bY R. Scott Lutz)'
HOW TO DESCRIBE BEHAVIOR
needs than in searching for something suitable in the literature. Also, you can prob-
ably save yourself a great deal of money.
4.2 HOW TO DESCRIBE BEHAVIOR
At the heart of the modern approach to the analysis of behavior in
animals is the problem of description. IMarler 1975.2 J
When developing a catalog of behaviors, you will be describing and applying
names to the behaviors you observe. For descriptive studies, your catalog (dis-
cussed below) can contain narnes for behaviors which carry implicit descriptions.
as well as dest'riptions which, by themselves, serve as terms lor those specific behav-
iors. As you shape your catalog of behaviors into an ethogram (discussed below)
you will probably apply ternts to the behaviors you have named and described, pri-
marily lor ease of data collection. For further ease of data collection. you may
replace the terms with code letters and nurrbers (Chapter 8). For experimental
studies. especially, you will further sharpen the descriptions into operational defin-
itions (Chapter 6).
The discussion below applies primarily to the early phases of a study in which
you are making reoonnaissance observations, taking ad lihitum field notes, or begin-
ning to compile a catalog of behaviors. Therefore, I have interspersed the words
'term','name' and'description' as synonyms.
4.2.t Empirical versus functional descriptions
As you first observe the behavior of an atnimal you will likely be conlused by the
complexity of what the anirnal does; but in tirne some order will appear in the types
of behavior engaged in, the contexts in which they appear, and the movements and
postures that are involved (Marler, 1975). Familiarity with an animal's behavior and
insight into its function are continuing processes that generally lead to revision of
both hypotheses and terminology.
Nevertheless, in time, it will be necessary to describe what you have observed in
terms which are clear yet unassuming. The problem of desoription is resolved
thror"rgh cxperience in observing the animal's behavior and your ability to select ter-
nrinrllrlgy that will assist, not hindel future analysis.
Thcrc irrc two birsic typcs o(' behuvioral description (see Tables 4.7 and 4.8):
Illilill'i,l;,:lllll :::ll J 'ill:,1,i'i:'::.]ill'rr 
i 
': '1e.':rs 'lrr 
bodv pa*s
' l:tttt, lrttttttl rlr'\r t tIlirtil. ltl( ()t l)()l;tlt()t) ()l tt'lt'tt'tlt't'lo lltt'llt'lt:tViot's littlt'-
Itiltr I1tr\ilil,tllr rrt trllrtrr,rlt'l\ (t'l' lr,rtr'tl lr'r'llt llttt';tl)
*mxru
Fig.4.3
82 R ECON NA I SSANCE OBS ERVATION
Table 4.7 . Erumple,s o./' empiric'al und.fint'tittnul dest'riptions ( ternts ) ./br
obsarvtttion o/ a flying ntourning tlove (see tert )
Type of descriPtion Behavior description
Emp i r i c u I de s c' r iP t i o ns
Fun t' t i o no I de s c r i P t i o tt,;
a. Behavior X
b. Rapid alternate contraction and relaxation of
the pectoralis muscle
c. Wing flapping
d. Flying
e. Escape flight
These types are nearly synonymous with the two types used by Hinde (1970): l'
clescription by spatio-temporal patterns of muscular contraction. including pat-
terns of limb ancl body movement;and 2. 'tlescription by consequence" respectively'
Wallace ( 1973) calls Hinde's first type 'description by operation'.
The type of clescription selected will depend in part on your knowledge of the
animal's behavior an<] type of study you wish to pursue' Descriptions can be thought
to lie along a continuum of inlormation conveyed. At some stage, conveying addi-
tional information generally entails <lrawing conclusions fiom data about function'
After careful study the researcher may be able to use a term which more clearly
describes the context of a behavior. For example, W. J. Smith ( 1968) studied the use of
the 'kit-ter' call by the eastern kingbircl (T)'rannus t)'runnu's) and concluded from
observational data that it provides information relative to the caller's indecision
about flying versus staying put, flying towards versus flying away' or flying versLls
landing. Hence, he labelecl the call the'locomotory hesitance vocalization''
As another example, let us say we are walking through a wheat stubble lield' ancl
50 m ahead of us a mourning clove flies up out of the stubble ancl lands itr a trcc -50lll
to our right. We can clescribe the behavior of the dove in flight r-rsing. at lcast' livc
dilferent levels of description(Table 4.7)'
Describing (i.e. naming) the behavior as'behavior X'provicles trs witlt tto ittlirl'-
mation unless we have access to a definition of the ethogratn coclc bcing ttsctl. l(ilPitl
alternate contraction and relaxation of the pectoralis rttusclc tclls trs sotttclltitllr
about the mechanics of the behavior but does not provicle thc cthologist r', rtlt tttttt'lt
useful information. Wingflappingcreates an imagc in thc tttitttl ol'tlrc ctltrilrtf isl.
but we d. n.t kn.w il-thc devc wus stunrling unrl lllrpl-rirrg its rviltps (Pt'tlt;t1rs:ttt
i.tcrtitln ur()vcurcnl)orlrctrrlrllv llvirrg. llv rlcscrihirrg tlrc lrt'ltrtViol lts llvittl'\\('r'('l I
elct,.e t. ltit.trrre ,l'tltr'llt.lurvior lrrrtlslrll;rtr'ttol ;tsstttllitll';ltttllttttt':tllottl 
tttttlr'tl\ tttt'
lllolt\;tltorr llt tlt..,t ttlrrrrt, tl ;t., (,.,(itI,' llrt,lil rrt' lll(' ll\\lllllllll' lll;rl lllt' tl.,t(' 
1'\'1"
HOW TO DESCRIBE BEHAVIOR
responding to a stimulus from which it was motivated to escape. We probably do not
really know if that was the true function of the flight or if, for example, it had fin-
ished feeding and was merely flying to the tree where it could rest with relatively
greater safety.
This example illustrates that the same behavior may be used in severalcontexts.
Mounting may occur in sexual or dominant-subordinate contexts in dogs, just as
urination may be marking or merely elimination (Bekoff, 1919b). Functional
descriptions should be avoided, except when the function is intuitively obvious (see
below) or supported by data, since they can be confusing and misleading (Marler,
1915) and lead to changes in terminology as the study progresses (Tinbergen, 1959).
The type of behavior, as well as the type of data being collected, often force the
use of both empirical and functional descriptions. Hinde (1970) suggests that since
threat and courtship behavior in birds involves both relatively stereotyped motor
patterns and an orientation with respect to the environment, both description by
operation (empirical) and consequence (functional) are necessary.
Eisenberg (1961) provided a list of behaviors lor rodents (Table 4.8) that
included both empirical and functionarl terms lor convenience of presentation. It is
useful to examine the list and identify those terms that are borderline, as well as
tl-rose that are clearly empirical or functional.
As Table 4.8 illustrates, the distinction between empiricaland functionaldescrip-
tions is not always clear-cut, so that the problern is generally resolved in terms of the
observer's intent. For example, does 'sniffing' imply searching lor olfactory stimuli
or merely wiggling the nose and vibrissae. This type of confusion over the observer's
intent is clarified through the definition of behavior units (discussed in section
(r.3.3 ).
Some descriptive terms are clearly f unctional, but they are readily accepted since
the motivation and goal of the behavior appears obvious. Fbr example, the terms
'nest building'and'egg retrieval'are accepted in ethological parlance, but they still
rnust be clearly described and/or defined for each species.
Your descriptions should inlorm others of your observations in an objective way
r','ithout bias to your own experiences or personal beliefs. Antltroportutrphisnt, the
rrttribution ol human characteristics to nonhuman animals. is often considered one
ol' thc gruvcst sins that an ethologist cern commit (Carthy. 1966); recently, the use of
;rnthrol-ronrorphisnr hy cthologists has become a more controversial topic.
,Arrllu'o1-rorrror'phisnr is lr lirrnr ol' 'l'unctional description' (described below), but
llow t'rrrr ue t'rrleg,orizc ils virrious lirr"nrs ol'usagc'l Is it a fatal flaw when used in
rt'st';rrclr'.' ('rrrr il. in lrrct. lrc rrsclirl to ctlrologists'l Antltroprorlorphism. as I'vc
tlt'lint'rl rl .rlrott'. ts otrl\ ont'ol tlrrct'lirtttts tlcscl'iltr'tl ltv'lir1toll'(l9ll7)rtntl is in tltc
( :rl('t'()r\ 'nrl('ll)r('lr\(' iurllr()l)()nr()rl)ln\nr ir('('(rtrltttl' lo I'isltr'r''s ( l()()0) scltctttc
(l t',1t,'t',lt,rttl,ll,,',,,tt',ttll,',ll,,1,1l,lttl,,',,,1,1t,'t',lt('t',1)('(lt\('()tlrtttllttr)l)()lllotlllttsttl).
83
R ECON NAISSANCE OBSERVATION
Table 4.8. List 0.f rodett gerteralmrtinterrunce behaviors utilizingboth 
entpir"it'ul and
.functional terms
HOW TO DESC]RIBE BEHAVIOR
Table 4.8. (cont.)
Sleeping ancl resting
Curled
Stretched
On ventrum
On back
Sitting
Locottttttitttt
On plane surface
Diagonal
QuadruPedal saltation
BiPedal walk
Bipedal saltation
JumPing
Climbing
Diagonal coordination
Fore and hind limb alteration
Swimming
Care ol the body su(ac'e and c'omf rtrt
m)vemenls
Washing
Mouthing the fur
Licking
Nibble
Wiping with the fbrePaws
Nibbling the toenails
Scratching
Sneezing
Cough
Sandbathing
Ventrttm rub
Side rub
Rolling over the back
Writhing
Stretch
Ytwtr
Slr:r kc
Care d the bodY sur.fat'e and
t'omJbrt movement,\
Defecation
Urination
Marking
Perineal drag
Ventral rub
Side rub
Ingestiort
Manipulatin with forePaws
Drinking (laPPing)
Gnawing (with incisors)
Chewing (with molars)
Swallowing
Holding with the forePaws
Gat he'r ing t'bodstulf.s and c'ac'hing
Sifting
Dragging, carrYing
Pickittg uP
Forepaws
Mouth
Hauling in
Chopping with incisors
Digging
Placing
Pushing with forePaws
Pushing with nose
Covering
Push
Pat
Diggirtg
ForePaw m()vemcllts
Kick hirck
Tttrtl lttttl lltrslr (lill'cllltw's ;ttttl lrtt'lrsl )
'l'ttrtt lttttl lltrslr (ttosc)
M oltlittl'
Nest building
Gathering
Stripping
Biting
Jerking
Holding
Pushing and patting
Combing
Molding
Depositing
Isolated animol exp loring
Elongate, investigatory
Upright
Testing the air
Rigid upright
Freeze (on all fours)
Escape leap
Sniffing the substrate
Whiskering
Sourc'e: From Eisenberg (1967).
Regardless of how strongly one might attempt to avoid anthropomorphisrn, it is
very diflficult, if not impossible, to do so (Crocker, l98l). It can be argued that we
cannot have knowledge of anything which we have not ourselves experienced either
directly or indirectly; therefore, researchers sometirnes unconsciously slip into its
trse (Kennedy, 1992). As Rioch (1967) has remarked, we are both limited and
tlirected by our vocabulary (symbolic behavior) in describing observed behavior.
I will readily admit that observation has one great drawback; it is hard
to convey to others. Experimental conditions oan be reproduced, pure
observation unfortunately cannot. Therefore it does not have the same
objective character. The observer who studies and records behavior
patterns of higher animals is up against a great difficulty. He is himself a
subject. so like the object he is observing that he cannot be truly
objective. The most 'objective'observer cannot escape drawing analogies
with his own psychological processes. Language itsell forces us to use
terms borrowed lrom our own experience. I Loren:, 1935:92 J
I tl'cnZ (1914) has also sr-rggested that in some instances the use of terms like'falling
rrr krve,' 'l-r'icndship'or''.jcak>usy'is not anthropomorphic, but rather refers to iunc-
lrolurll! rlctcrrrtinerl conccpts. In tliis regard. anthropomorphism might be useful as
r rrtctlrphot' lot'tlcscrihing wlrir( urt irnintirl does (Kennedy. 1992; Ristau, 1986) and
rrlrrrl ils'cnl()liorr;rl'rurtl ttroliv:rtiorrirl slirtcs ul)pcar ttr bc (c.g. I'car). witliout irlply-
rttl llt;tl \()nrr' l('\r'l ol t'orrsciorrs tlro111,,l11 is irrvolvctl. l'or exarrtple, tlrc 1'lht'itsc'tltc
,ltt1l 7r/1r1s',' lltc sr';t l)r()\ trlt's lts rr itlr ;r r tstt;tl itnrr;,,.' ;ur;rlo1'ous lrl ;1 1;g,',t.t"t''s 1'llrlw
;,rtslttltl';t\l(lt'lltr",,,rl \\"rlr't (l')S I l('/)ttolt". llt.tl '11llrtttktttt':tl16ttt lpltpttttttili,.'t
lr
l,
I
86 R ECON NAI SSAN CE OBSERVATION
lor manipulation in animal "ornpgnir:ation, 
analogies drawn from human interac-
tions tencl to dominate'; commonly used terms i,clude 
'cJeceit" 'selfishness" and
,spite'. wiley ( 1983: 167) concludes that the use of 
'these familiar words tnake visu-alization of technical discussions easier', but we should 
provide technical defini-
tions of the terms in order to 'guard against misleading 
inf-erences'
Where and how cloes the beginner draw the lir-re'l The 
saf-est approach is to avoid
using terms that could be misir-rterpreted an<l ttse only 
empirical descriptions' You
should especially consider avoi<ling terms which 
may be inflammatory and offen-
sive, as well as misleading. For example, Estep and 
Bruce (1981) argue against the
use of the term 'rape' by ethologists. An integral 
part of their argument goes beyond
Wiley's (1983) call for technical {efinitigns t6 the issue 
of redefining terms' stated as
lollows:
Beach(1978,197g)haswarnedbothofthedangeroftakingwordsfrom
Commonusageandapplyingspecializec]meaningtothemwithout
detrnition. ancl of resorting to Hurr-rpty-Durnptyism 
(taking a worcl from
commonusageandreclefiningittclmeanonlywhatyouwantitto
mean).Bothoftheseproblemsexistinthecurrentapplicationofthe
termrapetotron-hutnanbehavior.(E'stcpundBrttt,<',19s1..127))
What should we call behavior in nonhuman species that 
we know as rape in
humans?E,stepandBruce(1981)suggesttheterm'resisteclmating'asapurely
descriptive term. or we could use the term'lbrced copulation'(e.g. 
Sorenson' 1994)'
In summary. anthropomorphism can be perceived 
as a gradient:
t No anthroPomorPhism'
: Human terms technically defined'
I }{uman terms used as a nietaPhor'
+Humantermsfreelyusedwithalltheunderlyingimplications.
You shoul<l give consi<lerable thought to choosing at 
what point along the graclient
you will report your observa(ions'
Descriptiol]Sareoftenquantifiedtoclelineatemoreaccuratelyarrclctlrtlplctcly
deli'eate what the animal does when it performs the berravior. 
Surne cxa^plcs rl
thesequatltitativedescriptiorlsareillustratedinChapterl0.
4.2.2 Catalog, repertoire and ethogram
4.2.2a Catalog and rcPcrtoirc
HOW TO DESCRIBE BEHAVIOR
courtship), sex or age group we are interested in studying. The catalog is only a
portion of an anirnal's rapertoire - all the behaviors that tlie animal is capable of
perfbrming. We call the catalog tn ethogruri when we believe that it closely approxi-
mates the complete repertoire. The size of the repertoire will, ol course, vary from
species to species as well as between individuals, depending on sex, age and experi-
ence.
One decision that you must make during reconnaissance observations is when to
stop. When do you have sulficient inlormation to ask incisive questions, lormulate
precise hypotheses, and design a sound research project'l At what point do you have
a reasonably complete ethogram lor the animal(s)'l
If we were to observe an individual animal continuously lor an extended period
of time and record the behaviors that it showed, we could then plot the cumulative
number of observed behaviors by the time (Figure 4.4a).
An asymptote is reached after many hours of observation (arrow, Figure 4.1a).
beyond which few additional behaviors are seen for each unit of time spent observ-
ing. This asymptote may take tens, hundreds or thousands of hours to reach.
depending on the species studied. Nolan (1978), lbr example. spent 5524 hours
observing the behavior of prairie warblers (Dctrdroit'tt clist'olor), yet he saw only nine
copulations. If only one type of behavior (e.B.agonistic) is under study, then the
time to the asymptote will generally be shortened. Fagen and Goldman (1977:268)
concluded that 'familiarity with an animal's behavior will tend to require years of
experience if the animal is a mammal or bird with a complex repertory. But if the
animal's behavior is simple and relatively stereotyped such familiarity may be
gained in a lew months'. The objective ol'descriptive studies of a species (and to a
certain degree of developing an ethogram) is to determirre the true frequency of rare
or unusual behaviors. short-term stuclies record too many unusual behaviors. The
result is that we ofien overestimate the importance of some unusual behaviors since
we lack the perspective provided by long-term studies (Weatherhead, 1986).
Hailman and Sustare (1973) described an interesting laboratory exercise in'the
analytical power of biological observations'. The objective was to deduce the
'behavioral organization'of a talking, stuffed toy elephant Horton. The first step
consisted of listening to Horton's total vocal repertoire by pulling the string and
listing the vocalizations ernittecl. These data rvere transferreci to a cumulative graph
(lrigurc 4.,5) itncl cramitrccl hrr an asymptote to determine if the entire repertoire
Ir:rrl hccn rccorrlccl ulie r l(X) succcssive vocalizutions.
Attotltcr u':rv lo look irt thc hchaviorll rc;rertoire ol'an anirnal is through the
tirrrr'tk'rrrtetl to plrr'(icrrlrrr l'rchlrr,'iors (i.c. tirrrc htrrlgct) or by f'r'ctlucncy ol occrir-
r('n('('(llrtll;rrrtl llrrll.l()70).Sirrt'e llrt'l't'r't;u('lr('\'ol'occur.l-crrccvirt'icslirrthcbclurv-
t()ts ttt:tl);ttltttt;tl': t('l)r't lr,it,'.;t lrl,rl ol t'tttrtttlrtlt\('l)('l('('ttl:ll,r's ol'lol;11 litttc sPr'ttl itt
lltt't.rttott,lrt'lt;ttt,rt'.iil,,lttt',1 lltr'tt t.rtrL,'t,1,'t l,\ lt,'rllt('n(\ rrl otr'llt('ll('('tttllslt,,tt
81
I
88 R ECON NAI SSANCE OBSERVATION
MoSt
frequenl
Fig.4.4 A hypothetical example of cumulative number of different behaviors 
plottcd
against hours of observation. The arrow denotes the approximate asymptotc' b
Conceptual representation of an animal's repertoire plotted ats a cumulativc
percentage of the time spent in the various behaviors (adapted from Hutt lttrcl
Huu, 1970).
a curve which reaches an asymptote at the less frequently occurritlg bcltrtviots
(Figure 4.4b).
Fagen and Golclman (1977) rescarchccl mcthotls ol' ttrtitlyzittg llcltltviotrtl 
t'rtlrt
I.gs anclc..clurlcrl tSirt nros( rlistribtrtiorrs (ty1-rcs ol'bclrltviot'itl ttct/ittttttlrt't 
ol rtt'ts
tll-rscr.vctl )c.rrlrl l-lctlescriSctl hvlr loplrritltnricrelt,tr'ssiottslopt'ol ill)l)l()\illl:llt'lr'o 
\
(t'1' liil'ttlt"l (')
a
E-=10
oo=
:e ! 5
2"31
HOW TO DESCRIBE BEHAVIOR
0 10 20 30 40 50 60 70 80 90 100
Number of vocalizations recorded
The cumulative number of different vocalizations as a lunction of the total
number ol vocalizations recorded (from Hailman and Sustare,l9l3).
o'5
G
o
-o
c
o
o
=
o
o
.o
Elc
o
,2
a
f
E)
C)
Fig.4.5
c
oo
; 1oo
&eo
ioo
oj40
3so
ooi20
o
b
€o 10)z
5
'a
--t--t:?
--r-1'c. -nftT{--.a
=--c''-'-
;s
o
E
o
.z
o
f
E
f
(J
C)
lOO 2OO 5OO 1OOO m'00 5OOO 10000120000
Number of acts (tokens) seen
Fig.4.6 Plot of cat behavior data with fitted regression line Y:4.\lyr':c 1solid line) and
951Xr confidence bounds for regression line (dashed lines) (from Fagen and
Goldman, 1977).
Since the regression line has no finite asymptote, it does not allow the observer to
predict repertoire size. However, this procedure did encourage Fagen and Goldman
(1971:263) to recommend the following rule: A ten fold increase in the total number
ol acts will, on the average, double the number of behaviour types in the catalog'.
We can estimate t>ur .sumplc ('overage (0) bV calculating the probability that the
rrcxt bchuvioral act will be a new type (Fagen and Goldman, lgll). If 0 approaches
l. thc pnrblrbilily ol'obscrvirlg u new behavioral act is low.
.t/0I'
I
A', ts llrt'ttttntlrt't ol lrr'lt;tviot l\'1lt's s('('n ()nlV ()n('('. lrtttl /ct1tt:rls llrc totirl nrrnrhcr
ol lrt l\',('('n Wlrctr ,\', rr snr;rll tt'llrll\r'lo / llrt'rr orrrll ;rPProlrt'lr I. llrt't'loser tlrtrt [)
Hours of observation or number of behavior acts observed
Rank order of behaviors by frequency of occurrence
90 R ECON NAI SSANCE OBSERVATION
approaches 1, the more complete the sample coverage. For example, S' Altmann
(1965) observed 5507 acts in rhesus monkeys and saw 32 behavioraltypes only once'
^3?tt-- t- '- :0.9942
s507
This indicates that Altmann's sample coverage was essentially complete' Fagen and
Goldman (1917)caution that this method emphasizes the significance of rare behav-
ioral acts. They provicle a morecomplex procedure lor estimating the repertory frac-
tion which properly weighs the frequency of occurrence of different behavioral types'
Of primary importance to any ethological study and particularly to a considera-
tion of catalogs and repertoires is a determination of a behavioral unit. The size of
the catalog will vary according to the way in which behavioral units have been
dcfined. The more inclusive (i.e. lumping several dilferent behavioral acts, such as
threat and submission, into a single behavioral unit - agonistic behavior), yet mutu-
ally exclusive (e.g., agonistic versus ingestive; see below), the smaller the catalog will
be. The selection and definition of behavior units will vary according to the objec-
tives an<l logistics of the individual study (Chapter 6)'
4.2.2h Ethogram
A, ethogram is a set of comprehensive descriptions of the characteristic behavior
patterns of a species ( Brown, lg7 5).lt is the result of refining your catalog of behav-
iors after many hours of observation (in some cases audio recording) and descrip-
tion. and it should be the starting point lor any ethological research' especially
species-oriented research. Schleidt et ul. (1984) provide a brief history of the use of
ethograms by ethologists.
When concept-oriented research is conducted, researchers may compile an
ethogram of only those behaviors within, or closely related to. the category in which
they are interested. For example, Fraser and Nelson (1984) compiled an ethggrttn1
of the courtship behaviors of male ancl female Madagascan hissing c6ckroachcs
(Gro m p h atlrt rh inu p o r t e n t o s u) (Table 4'9)'
Limiting our knowledge, as well as our research. to only one typc tll'bchitvior itt
a species does pose potential hazarcls. For example. Tinbergen (1953)itrgtrctl thrtt
the more we restrict our view of the animal's totalbehavior pattcrtts. tltc gt'crtlcl'tltc
probability of misinterpreting results.
The need lbr a broacl. ttbservatitlnitl apprtllch crtrttl()t bc stt'cssctl loo
much. Thc ttatttritl tcrltlctrcy ol' tttittty llcoplc. pltt'ticttlltt'iv lrl yottrtl'
hCgipsCt's. is ltl Ctlttt'ctllt'ltlc ()ll illl isollttctl lltolllt'ttt lttltl lo ltV lo
lx'1(.ltitl(.i1to il I ltrs l;rrrrllrlrlr'rrrr'liturti()ll llltlsl lrt'l't'Pl irr t ltt't l' 
t'l t'l"t'
il lt.lrtlr l() ;ttt ;l( ( tllttttl;tltott ,,l lr:tt lt;tl tll',t oltttt't lt'tl t'""ttll'- lo 'l '
HOW TO DESCRIBE BEHAVIOR
Table 4.9. Court.ship behuvior,s perfornted by ntula and./bmale Maclagas('an his.sing
c'oc'kroucltes
Behavioral unit Description
9t
Approach
Antennate
Hiss
Mount and
palpate
Posture
Cross-over
Copulation
attempt
Stanci
Movc irwiry
One animal (either male or female) moves lorward and
makes contact with the other animal
Two behaviors can be distinguished: mutual antennation by
both male and female where contact is antennae*antennae;
and solo male or lemale antennation of the other animal's
dorsal surface. The latter form of antennation can take the
lorm of 'tapping' or'horizontal rubbing' movements. These
movements are very different lrom the rapid vertical 'fencing'
movements of aggressive behavior (Nelson and Fraser 1980)
This audible sound results from the lorcef ul expulsion of air
through a specialized abdominal spiracle. Male courtship
hissing can be separated by its acoustic characteristics and
behavioral context into type-l and type-2 hissing. Type-l
hisses are isolated, soft hisses, whereas type-2 hisses are
shorter and occur in trains (for a more detailed description of
the acoustics of sound production, see Nelson and Fraser,
1 980)
One animal puts one or more legs on the other and taps the
other animal's body surface, usually the dorsum. with the
labial or the mandibular palps
Male stands high olf the substrate with the abdomen curved
upward and extended. This is sometimes accompanied by
extrusion of the phallomeres and/or type-l hissing. During
posturing a distinct odour is noticeable to the (human)
observer
Female crawls over the posterior tip of the male's abdomen,
dragging her abdomen over his
Male attempts to copulate by rapidly thrusting the tip of the
abdomen towards the flemale's abdomen. Usually the male
starts thrusting towards the lateral ventral surface of the
f'emale abdomen, moving to an opposed position for
copulation
Fernale stands with legs braced laterally, body close to the
gror,rnd. the abdomen flexed downward at the tip. This
normally rrccompanies copulation attempts by the male
Onc or both unimals walk or rLln away from each other
Nrtlt'.'
lrrrrrrr l'r:rst'r rurrl Nr'lsorr (l()l'i,l)
,\'rllr r' '{ ',,;,1 ,rl,ltlt'rl lrt' ll;rrllrt'rc trrrrllrll
R ECON NAI SSANCE O BSERVATION
collection of sociological oddities. A broad, descriptive reconnarissance
of the whole system of phenomena is necessary in order to see each
individual problern in its perspective; it is the only saleguard for a
balanced approach in which analytical and synthetical thinking can
cooperate. This, of course, is true not only of sociology, it is true of each
sc-ience, but in ethology and sociology it is perhaps forgotten more often
than in other sciences. ITinbergcn, 1953. I 30 J
Descriptions of the behaviors in the ethogram should be clear and concise. yet
complete. A useful adjunct to a written description is a photograph or line drawing.
Figure 4.7 shows how Enqr,rtst et al. (1985) used line drawings to supplement the
written descriptions in tlieir ethogram of behaviors performed by lulmars
(Fulmurus glacialis) when competing for fish.
Schleidt et a\.11984) pointed out the large variation in description, format and
completeness of published ethograms. They designed a 'standard ethogram'which
they hoped would serve as a prototype for future ethograms of birds and, perhaps,
other taxa. The ethogram, which consists of the 60 most commonly observed visual
behavior patterns, was tested and refined in a study of the bluebreasted quail
(C o tur nix c h ine n s is).
The discussion above dealt with ethograms for descriptive studies or experimen-
tal studies of normal behaviors in a naturalenvironment. An ethogram of behaviors
to be measured is also compiled when conducting a manipulation experiment (e.g.
Godwin, 1994); in this case, the behaviors are operationally defined, instead of
being described (Chapter 6), and they are normally mutually exclusive.
4.2.2c Mutually exclusive behaviors
Mutr-rally exclusive behaviors are those that cannot occur simultaneously, either
because the anirnal cannot perform them simultaneously or we have defined them so
as to eliminate two behaviors being recorded simultaneously. The behaviors
described in your ethogram must be mutually exclusive if you are determining tirle
budgets (i.e. the amount and percentage of time devoted to each behavior). Time
budget studies also require that your ethogram be erhuu^stive (i.e. the animal musl
always be engaged in one of the behaviors in your catalog). Also, the bchaviors nreu-
sured in an experimental study are almost always defined scl that thcy:rrc nrrrtuirlly
exclusive, so that the animal is recorded as responding with only onc o('scvcrrl pos-
sible behaviors (see Chapter 6).
The behaviors in your ethogrtv:n .slttttrld hc nrutually cxclrrsivc il' yorr lr rc rrrrlrlllc lr r
rccorcl ltccttrittcly Inttrc tltittt tlttc l'lelurv'iol'lrt orrcc. eillrcr l'reclrrrsc ril'.\,orrr l;rt'k ol
cx1'rct'icttcC rlt'hcclttlst. y()tl :ll('ttrirtl'tt tlltt;t lrl1.,1't't (()l s()ll1'lttt')llr;rl trrll ttttl ttll,*
lrtr tlrt'tr't'otrlittl',rl sintttlt;tlt('(rus ltt'ltrrr tols (( 'lurPlt'r ()l
Bill-pointing' The bird points with the bill against the opponent. This behaviour varies in inten_sity from a turn of the hearJ to an unsuccessful attempt to peck the opponent. The mouth isoften open and a sharp sound is utterred. The owner also directs this behavior to flying birds.Bill-pointing is always cornbined with Wing_r.aising.
HOW TO DESCRIBE BEHAVIOR
Breast-to-braasr' The two birds meet, orientating the body somewhat uprightwith theirbreasts touching' Breast-to-breast is nearly always preceded with rushing behavior performedby one, or both, bir<Js.
Fig' 4'7 Line drawings a,d descriptions of two behavior patterns performed by fulmars
when competing lor rood (rrorn Enquist at nr., r9g5). Copyright by BaiiliereTindall.
Using only mutually exclusive behaviors may provide a high enough level of res-olution to answer some research questions, but it is unrealistic to believe that it willaccurately reflect the animal's true behavior. Probably all animals are capable of,and do perform, simultaneous behaviors.
.I.] INI;ORMAT-IoN RESoURCES
'['ltc trsrrirlll'ltcccl-tlctl tlogtna states that befbre embarking on your research yousltottltl lr"lttll:ts ttlrtcll ils v()r-r citn irboul yorrr sub.iect aninral, especially about itsbclr:rv'r.1. lr.\\'r'r'r.'r. trris rrrigrrr rr.t rrrwlrys hc rr.rrc (scc sccti., 4.3.r). v.,, srro,ldt'.llt't'l lllt.11;1;11i,tt' ttt:rrlrlili'rtl l, \',trt irrili;rlrr'r'.rrrrrrissr,rr.c.bscl.vlrtirlas. {l..l, itll(llt'\()lll(('\ ll \()lll rltrp,",;11. trr,'lrr.lrrrl';rr;ul:rlllt'lilt.t;rlr1t.. rl;tllr ll.tlltt tllltet.
94 RECONN AISSANCE OBSERVATION
researchers'efforts (personal interviews, logs. diaries, field notes, etc'), and films and
videotapes.
4.3.1 Literature
How much time shoul<l you devote to reading and reviewing the literature'l The
Answer depends on several factors. First. for clescriptive studies' a review of the liter-
ature might provide you witli biases and a restricted, myopic view of the behavior'
and prejudice your observations. Secondly, beginning researchers can spend too
much time acquiring a breaclth of knowleclge in their fielcl' P'B' Medawar' a Nobel
prize winnilg experintental pathologist, offers the following in his Advice to a Ytung
St'ienti,st'.
. . . considerations apply to a novice's inclination to spend weeks or
months'mastering the literature.'Too much book learning may crab
and confine the imagination, and endless poring over the research of
others is sometimes psychologically a research strbstitute. . . .The
beginner must read, but intently and choosily and not too much. Few
slghts are sadder than that of a young research worker always to be seen
hunched over journals in the library; by far the best way to become
proficient in research is to get on with it I hlt'tlavur, 1979: 16,l7 ]
Researchers'inability to read and absorb the enormous body of published infor-
mation available. while stillconducting their owlt research, is a widespread phenom-
enon. Thomson, in his informative discourse on the state of scientific literature said:
The ultilrate irony is that a major proportion of the 'literature.' st>
expensively and llerve-wrackingly produced, is rarely read or cited' ' ' ' if
only because of the simple fact that so much is published' even in the
.post narrowly defined fielcls. that one cannot both read it all and still
have time to add one's own peerless contribtrtions. ITlutnr';ort, 1984:18-t ]
However, for experimental studies it is generally advisable to be current on the btltly
of knowledge available about the cgucept or species yoLl are strrclyilg' This will hclp
you to generate new hypotheses and avoid unknowingly duplicating sotl-tcottc clsc's
research. Even this approach may consume much of the time yo1t wotrltl prclcl'
spenclilg on your own research. For example, S.E. Luria (1984). it Nrtbcl l)rizc
winning microbiologist, acknowledges that he is not 'iln cttgcr scckcr ol' iltlirl'lttlt-
tion'.
I like to operate with rtnly a ll'irctiorr tll'tltc cll()t'lll()tls ltccttlltttlltliott ol
kl6wlctlgc. Wltcrr I rrl)cn il t)cw issrrt'ol'lt st'ir.'ttlilit'iorrrtrlrl I tlo t)ol st'ltlt
tlle t:rllle ol't'otltr.'llts lookittl' lot t'rt'ilitll' tlo'"t'll1' ott lltt't'oltlt;ttt' I
Ittrlrt.ll.;rl tltr'tt't',tll lrt'ttt,llttttl'ttt tl tllltl I tttrtsl tt';ttl r I tttr't' lt)'\'l I l'
HOW TO DESCRIBE BEHAVIOR
When you reach the level of experience and stature clf a Nobel laureate, your
research will be the 'cutting edge'; perhaps then your mind will generate sufficient
ideas and direction to keep your research on a productive course. I assume that the
reader of this book has not reached tliat level.
There are lour classes of literature which can be read and reviewed (Fenner and
Armstrong, 1981):
Pre-primary literature includes'in-group' memos and technical reports.
These are produced primarily in state and lederal agencies and industry.
Beginning ethologists, especially those in academia, will have limited
access to the pre-primary literature.
Priniary literatr,rre includes all tlie prof-essionaljournals in animal behav-
ior or related disciplines. Journal articles will be the best written source ol
cietailed information about research on species or concepts of interest.
Secondary literature inclr"rdes indexes and abstracts of the primary litera-
ture that are compiled by various services, such as Anintal Behuviour
Ab.stratl.s.
+ Tertiary literature includes syntheses of the literatr-rre such as textbooks,
encyclopedias and handbooks. Tertiary literature is often where a begin-
ning ethologist's interest in particular specics and concepts begins.
Access to prirnary literature fiournal articles) can be sought in three ways.
First, ref-er to a recent article on the topic. You can find one by looking in a recent
secondetry source (see below),in Current ('ontents La/b S<'ient'e.t. by searching one
of the journal online catalogs such as Unc'over, Articlel,st and C'ontentslst, or by
asking a researcher in that area. Look at the articles relerenced by the author.
These articles will often be of interest to yor-r. By reading these articles and using
their ref-erence lists. you can go back many years, sometimes to the original paper
trn the subject.
Second. you can r-rse the secondary literature (indexing and abstracting tools)
which provide references to journal articles by subject. Since most of these tools are
now prodr.rced by computer. they can be searched in three ways: through the printecl
issues. online through commercial vendors such as Dialog and STN, and on CD-
ItOM in libraries ()r on your own conrputer using Internet. Bitnet or other zrccesses
to thc inlirt'nrittion 'sLrperltighway'. Some are now available as part of online cata-
Iogs ol' librirries. Onlinc ancl CD-ROM versions generally do not cover the entire
nurgc ol'vcru's llrrl lrirvc l-rccn pLrblishcd. For example. the online version of
llirtlrt,tlit trl .llt,:ttttt lr (lliosis) c()vcts l9(r9 lo thc prcscnt: the CD-ROM versiorr
('()\'('ts l()fi : lo lltr' Prr's('nl. llrt' pr irtl re rsiorr c()vcrs l()l(r trl thc prcscnt. Dittes ot'
t'lt't'ltrllll( \('l\lr)ll\. ('\l)('( titllt lrt llrr'( l ) l{( )N,l lir1 111',1. ;rrt' likelV lp CltiltgC irt thC
Ittltttr',1'.rr()tt'()l111'1 1rt trlt'tl t',\lt(",,l|('lr,ilr',trtlrr'tl l();l (()llll)il1('l tt'tttlltllle l0tttItt.
95
R ECON N AISSANCE, OBSERVATION
Several steps are involved in conducting a literature search, either using 
printed
sources or electronic formats:
tWriteashortSentenceorparagraphstatingyourneed'
z Decide if you want a lew relevant articles or'everything'.
I Divide your search topic into concepts and label them.
+Undereachconceptlabel,writeappropriateterms(keywords).
s Decide on appropriate abstracting and indexing services or databases to
search.
Review instructions on access points in each service or database (title
words, assigned subject headings, subject codes, etc')'
For electronic formats, select appropriate Boolean operators (and, or,
not). For example, 'dogs and wolves, not prairie dogs''
Do the search.
Look at your results and go through steps 1-8 again with new words or
terms suggested in articles identified'
There are usually several ways of conducting any literature search' Your success 
will
often depend on how well you know the area of research and the researchers 
that are
publishing.
Third, you can scan the yearly indexes in the professional journals where 
you
suspect articleson your specific topic may have been published' These, 
if they exist'
can usually be found at the back of the last issue in each volume' Also' search 
the
subject indexes in the tertiary literature (textbooks) on animal behavior'
Fourth, if you know a classic or original paper on a subject, you can find out who
is currently citing it by using the citation index portions of St'ienc'e Citotion Index
(SCI) and Soc'ial Sc'ience Citation Inclex (SSCI). SCI and SSCI work on the same
principle as the first method above, by telling you who is citing what' SCI and 
SSCI
also have author (name) indexes and key-word-in-title subject indexes'
Other sources of information about current research are programs' published
abstracts, and published proceedings of scientific meetings' Addresses of 
presenters
are usually provided, an<l you can write the author directly for more inlornratit'rn 
t-rr
a copy o[ the manuscriPt.
Monographs and books are aiso important sources of informatit)tl otr itrlitllitl
behavior. It is not unusual for long-term studies to be published in this ftr,r,t. .lir.c
Goodall, for example, first published her observations on thc chitnpltttzccs 
irt lllc
Gombe Stream Reserve as one volume in the Aninurl Bt'hut'iortr Mttttogt'lt1'rlt 
scl'ies.
but her most well-kn.wn work is thc book Itr rltt, ,\lttrrltnr of Lltttr. Ptrblislrctl 
irt l()7 I '
B.oks cul hc lilulrl hy searclrirrg strbiccts itt ottlittc cltlitlogs ot tltt'ttlttliliottrrl
cirt-tl cltlltlttp.s ol'lillrlrrit's' ltt cltttl t'lttltlol''s' t'llit'it'rtt il('t'ess is lrt'sl olrl;tittt'tl 
lrv lirsl
rt.lt.rri,1,l. tlrt'I tlrt;tty ol ( ()lll'l('\\ Srtlrlt't't Ilt';ttlitll's ( I\llr r'tlrr l()()')) tttrrlt't 
lltt'
HOW TO DESCRIBE BEHAVIOR
phrase Animals, habits and behavior of'lollowing the name of the species of inter-
est. Online catalogs allow you to access single words in titles, plus subject headings
and authors.
The United States government is the world's largest publisher. Many important
publications are produced by various agencies within the Departments of
Agriculture and Interior. These can be identified in online catalogs and in the publi-
cation from the Government Printing Office entitled Monthly Cutalog of United
States Government Puhlication^y. Federal and state documents may be available from
local or state offices of governmental agencies. They should also be available in state
government depository libraries.
The world of information is changing almost daily. Indexes and abstract jour-
nals were once available only through the printed format which required tedious,
laborious and time consuming 'manual' searching. Today, the same indexes and
abstracts can be searched (with the results printed) in a few minutes. Tomorrow,
they will be readily and widely available through the electronic networks or online
library catalogs using your office and home computer. A reference librarian at a uni-
versity or public library will be able to tell you the current status of availability of
these services.
Once you have a growing list of citations of references you should consider using
a microcomputer (see Appendix B) and a reference manager software package for
easy storage and retrieval of references. Most software packages will allow you to
retrieve references by various key words in the title, journal and author. Some will
print your selected list of citations in the format required by the professional journal
where you will submit your publication. Four of the more popular reference man-
rrgers are ProCite (Personal Bibliographic Software, Inc. P.O. Box 4250, Ann Arboq
M I 48106, USA; or Woodside, Hinksey Hill, Oxford 0X I 5AU, England), Refbrence
Munoger (Research Information Systems, Inc. 2355 Camino Vida Roble, Carlsbad,
('A 92009-1572, USA, EndNote (Niles and Associates, Inc. 2000 Hearst St.,
llcrkeley, CA 94109, USA), and Papyrzrs (Research Software Design, 2718 S. W.
Kclly St., Portland, OR 97201, USA).
1.3.2 Other researchers
( 'orrtlct othcr rcscarchers who are working (or have worked) on concepts or species
rrr wlriclr you ru'c intcrcstccl. Discr-rss your proposed research relative to your own
itlerrs. l)o rrol prrrirsilizc irntl irsk clucstiotrs that imply'Tellme everything you know
rlrorrt . . .'. Mosl rt'seru't'lrcrs;rrc gllrtl lo tliscuss ongrling proiects, but are unwilling
Ioprorirlcrrrirri lr't'lrrrt'slor pt'o1llr'wltolt;tvr'rtrll rtlt'citrlyittlcntptetl tolcarnasmuch
,rr lltt'\ r';ttt lltt()ul'll olltt'l sr)tlt(('s
98 R ECON NA I SSANCE OBS ERVATION
4.3.2a Pro.fessional meetings
professional meetings, such as the Annual Meeting of the Animal Behavior Society.
are excellent opportunities not only to expand your knowledge about the various
behaviors of a wide variety of species, but also to meet and talk with other
researchers. Question and answer sessions lollow the technical paper presentations,
and hallways ancl lobbies always 'buzz'with more infbrmal discussions. Always,
realize and respect the fact that most prolessionals are cautious about divulging the
crucial details of their research until it is nearing completion, has been presented at
a meeting, or is in published form. Young ethologists are strongly encouraged to
attend, present papers, and join in the discussions at every prof'essionalmeeting pos-
sible.
4.3.2h Telecommunications
It is now possible to quickly contact many researchers through electronic mail (E-
mail). Some researchers are willing to carry on extended discussions about research
questions, designs. proceclures, results, and numerous other topics over E-mail'
Keep in mincl the caveat given above that most prolessionals are cautiotts about dis-
cussing crucial aspects of their own research during its early stages.
There are also several electronic bulletin boards and newsletters devoted to
animal behavior. For example, you can subscribe to ABSnet by contacting -lim Ha
via E-mail:jcha(a)milton.u.washington.edu. See Appendix B for further discussion
of telecommunications.
4.3.3 Films and videotaPes
Films and videotapes are additional sollrces of preliminary information about an
animal's behavior. Viewing films before embarking on a project is a strategy per-
lected by successtul fbotball coaches. In most cases, the more familiar you are witl'l
the animal, the greater the probability ol success in your project.
Other researchers are oflen willing to discuss not only their rcsearch atlcl yottr
proposed project with you, but will often loan motion-picture totltagc atrtl viclco-
tapes to responsible investigators.
Another source of films and videotapes is film librarics. whe rc trrtcilitctl lirotitgc
or polished pro<luctions can be rented for a nominal t'ee. Ftlttr tll'thcsc sottt'ccs ill'c
listed below:
Encyclopaecl ia Ci rlenlrtt ogntpll icrt A I'cll i vc
I lrc l'ctut St:rlc I Iltivctsitv
ll I Mitclrell Iltriltlirtl
l lirirt'rsrlr l'lrtl. l'.\ l('l'io ) llS,'\
I
f How ro DESCRIBE BEHAVIoR
Audio VisualServices
The Penn State University
l7 Willard Building
University Park, PA 16802, USA
Rockefeller University Film Service
Boxl2
1230 York Avenue
NewYork. NY 10021, USA
UCLA Media Center
Instructional Media Library
99
405 Hilgard Avenue
Royce Hall No. 8
Los Angeles, CA 90024, USA
Companies that provide hlm and videotape lootage to production companies for
incorporation into programs are another potential source fbr ethologists. Three of
these companies are:
Dreamlight Images 932
N. LaBrea Ave., Suite C
Hollywood, CA 90038, USA
Energy Production
2690 Beachwood Dr.
Los Angeles, CA 90068, USA
Fabulous Footage. Inc.
l9 Mercer St.
Toronto. Ontario M5V 1H2
Canada
A rel-erence fbr approximately 140000 commercial videotape programs and
ncarly 2000 sources is Klisz (1995). The Video Source Book.2 vols. Gale Research
Inc.. 83-5 Penobscot Bldg., Detroit. MI. 3988pp. Additional sources of films and
vidcotllrcs citn be obtained by contacting the chair of the Animal Behavior
Socicty's Iiilnr ('onrniittcc and educationalmedia departments at colleges and uni-
vcrsi(rcs.
CONCEPTUALIZI NG TH E PROBLEM
observation of the goings-on in a gullery faces one with a great number
of problems - more problems, as a matter of fact, than one could hope
to solve in a lifetime.
The real problem arises when we attempt to isolate and define a question, or a
group of related questions. A clear statement of the question (problem) in scientific
research is perhaps one of the most dilficult steps in a continuing process (see
Bronowski, 1973).
It is imperative that your research question clearly addresses the knowledge you
are attempting to obtain (see also Barnard et a|.,1993). For example, Miller (1985)
states that in studies of learning there are two types of question which reflect differ-
ent concepts: l. Can questions address learning capabilities of animals, such as 'Can
species X learn by higher-order classical conditioning?'; 2. Does questions are more
ecologically oriented. such as 'Does species Xlearn behavior I'by higher-order clas-
sical conditioning?'Examples of clear and concise ethological research questions
are quoted in section 5.2 from Crump's ( 1988) study of aggression in harlequin frogs
(Atelopus vurius).
" A duplicative type of research can result because you have an interest in a ques-
tion that has already been addressed by another researcher. Perhaps, you are not
convinced, based on your own observations, that you would get the same results if
you replit'atecl their study. There are two types of replication studies (Martin and
Bateson, 1986): l. Literal raplic'ation is an attempt to duplicate the study exactly
using the same methods and species under the same conditions;this would provide a
test of the internal validity of the other researcher's results; 2. Con,\tltc'tive replic'a-
tion involves the use of other measures, similar conditions, or other species to deter-
mine whether the same (or similar) results provide external validity for the other
researcher's results (internal and external validity are discussed in Chapter 6).
Although replicating someone else's research may seem mundane to an established
researcher, it can be a valuable experience lor a beginning scientist. as described by
Medawar (1979:17):
It is psychologically rnost importzrnt to g?/ reslllts, even if they are not
original. Getting results, even by repeating another's work, brings with
it grcat accession to self-confidence; the young scientist feels himself one
ol'thc club at last, can chip in at seminars and at scientific meetings with
'My own cxperience wirs. . .'or'I got exactly the same results'. . .
Wlrrlcvcr y()ur'(lucstion. you must be committed to it and genuinely interested in
rrrrsrvcrirrl.r tlr:rt tlrrcstrorr: othcrwisc. you nright be prone to making observer errors,
('ll()l\ ol lt't'ottlittl' ;ttttl/op e()llll)tllillipltitl ct'trl;s (('[11ltcr 8). Thlrt is. if yOu are
('()nl('lrl lrr 1111'1r'lf lirrrl (///;ttrs\\'('r to lltc lt'st'ltt'clt t;trcstiott. t-lttltcr thltn //tc iutswer.
\'()u ntit\ ,tllrrrr \otlst'll lo t ontlttr'l tttr;tltrl tt'st';ttt'lt
s Delineation of research
5I CONCEPTUALTZTNG THE PROBLEM
A separate chapter has been devoted to the concepts discussed below because 
of
their relatively great importance. Proper clelineation of research is the cornerstone
of any successful study. A commotr f ault among many beginning researchers 
is their
inability to state clearly the questions they are attempting to answer and 
the objec-
tives they are striving to meet (see also Barnard et al., 1993)' Before the actual
research can begin you must decide what yott are trying to accomplish' As 
men-
tioned in Chapter l, most of our activities in ethology will be concerned with
hypotheses-testing in a broad or specific manner (discussed later)' Broadly 
defined'
hypotheses arise from a process of observation-question-hypothesis' Questions
and hypotheses are a natural product of our thought processes and cannot be
turned off and on. Therefore, while we are reading, observing animals. or 
listening
to other researchers, we are constantly generating questions and formulating
hypotheses. Medawar ( 1960:73), in a discussion of the scientific method' stated 
his
belief that hypotheses arise as follows:
So far as I can tell from my own experience and lrom discussion with my
colleagues, hypotheses are thought up and not thought out' One simply
,has an idea'and has it whole and suddenly, without a period of
gestation in the conscious rnind' The creation of iit.t lrypothesis is akin
to, and just as obscure in origin as. any other creative act of mind'
The thought processes from which questions and hypotheses are born should 
be
allowed to run f ree cluring our initial reconnaissance observations, but 
they must be
held in check durilg actual data collection when bias may creep in (Chaptcr 
tl)'
s.l.l What are the questions?
Ethologists are never really at a loss for questions. We ttre ctlnstrttttly 
gcncrlrlirlg
questions as we observe animals (Lorenz, l99l) ancl prtrsttc otll'owtt t'cscrtt'cll'
Reflecting on his many years ol'rescarch on hcrring gtrlls.-l'irtbcrgert 
(l(xrolr:rrr)
statecl:
Srl.tt ltl'lr..r'stlttlittl,stt('ll ll sltttlV.l ll s.t'i:rl lltttl's t'.tttttlttlttlt' ltlt" .ttt'
11r.1,11'r lo tt.;rlrzt.lt,rtt lttllt.,rtrt'Inil\\\ ltYt'tt ;ltt lt,,ttl", (;ll('llll
102 DILENEATION OF RESEARCH
s.l.2 Stating obiectives
The objective of research, as statecl above, is to answer one or more 
questions' The
research objective should be stated as a goal' not a method'
For example, an ethologist may be studying social behavior in 
domestic chickens'
It is noticed that the frequency of agonistic encounters appears to vary 
with flock
size. But cloes it vary systematically'? A suitable research question is: 
What is the
relationship between flock size ancl frequency of agonistic encounters'l 
The research
objective would be stated as:
. To tletet.nrine whether there is a relationship between flock size and fre-
quency of agonistic acts in domestic chickens;
' tl)l us'.
. To rtrca,;ure thefrequency of agonistic acts in flocks of diff-erent sizes in
domestic chickens'
The overall objective of experimental stu{ies. such as that 
just mentioned' is to
answer a question through tests of an hypothesis'
s.1.3 Research hYPotheses
As discussed in Chapter 1, hypotheses may be of a broad undefined 
nature or spe-
cific and defined in such a way that they can be experimentally tested' 
Specific
hypotheses are of two types: reseurch ltv'potheses and ^r1rr1i^l'ticul ltypttthc';es'
Statistical hypotheses are the outgrowth of research hypotheses 
and erre the basis fbr
statistical tests; they will be discussed in Chapters I I to l7'
Research hypotheses are conjectural statements about behavior 
and other
related variables. They are what you perceive to be the 
'true situation" From the
example in the previous section, your research hypothesis might 
be that agonistic
encounters increase as flock size increases. This is the relationship 
that yor'r hclicvc
exists between the behavior (agonistic encounters) and an indepenclcnt 
variitblc
(flock size). ln science we progress from pos,;ibilitic^i (questitlrrs). to prutlttrltilitit''t
(research hypotheses, basecl on limitecl observatiilns). to ut't't'ltltrhlc ltntltttltilitit"t'
(based on experiments. statistical hypotheses, and statistical tcsts)'
Generally, the transition from question to rcscitrch hy1-rothcsis is [Itsctl 
olt
thought and careful consicleration of tlhservatitltrs itttcl. itt sotttc cltscs' Ptt'tiotts
experiments. F()r cxample. in l9(r6. Hirmilton introrlrrccrl tlrc lirllortitt!' 
test'rttt lt
hypothcsis:
'I llt't'ttt tt'ttt t'r1ll;tttltlitttl ol V lirt ttl;tlioits irt llirtl llot l'r ts lll;tl lltt'r
,'sl:rlrlt:lt l;trt't;tlrlt'illl ( lll lt'ttl" lt'rlttt trrt' lltt'lrt ('ll('ll'\ l('(lllll('lll('lll" 
'\ll
USING THE MODEL F'OR A BEHAVIORAL ACT
alternative hypothesis is proposed here, that this flock structure isa lorm
of orientation communication, enabling the individuals of these flocks
to take maximal advantage of the collective orientation experience of
the group. IHuntilron, 1966:64J
Lissaman and Shollenberger (1970), provided evidence in support of the hypothesis
of reduced flight energy, but Hamilton's alternative hypothesis remains untested (as
f'ar as I am aware).
Unlike the thinking that went into Hamilton's hypothesis (above), the transition
ll'om a question to a research hypothesis can sometimes be rather sudden, with the
researcher not fully aware that they are fbrmulating in their mind a probable answer
(research hypothesis) to a question they have been pondering. In fact, Medawar
( 1960) has suggested that this sudden leap of insight is the normal mechanism lor
generating hypotheses.
5.2 USING THE MODEL FOR A BEHAVIORAL ACT
A f urther look at Crump's (1988) study of aggression in harlequin frogs (Atebpus
ruriu,t) (mentioned above) provides an example of how the Model lor a behavioral
act (Chapter 2) can be used to help delineate research. During preliminary studies in
('osta Rica, Crump: l. lbund that individual fiogs were abundant along a stream
throughout the year; 2. observed site fidelity and aggression in both males and
lcn'rales, 3. observed that after intrasexualaggression the loser left the area resulting
in more even spacing among individuals; and 4. observed unusual intersexual
aggression. Therelore, this population of l-rarlequin frogs provided Crump with the
o1-rportunity to address several questions about the function and causation of their
lggression that cor"rld be compared to other anuran species and other animal
s11)Lrps; tlrat is. this population met both the .suitubilit-v and avuilubility criteria
(('hapter3).
The numbers ol the statement and questions below correspond to the numbers
in Iiigurc 5.1 showing where they Iit into the model. The only type of question not
rrtlrlrcsscd in this reseurch was a 'How'question.
I ('r'rrnr1-r f irst hacl to cle(ifie operartionally l0 behavioral patterns involved in
I Irc ll'ous' irr:glcssivc cnc()r.lntcrs.
' 'Arc tlrcrc scrrsonaltlillcrcnccs in behavioralinteractions among fiogs,
:rnrl il so. tlo tlrcv rcl:rlc lo tinring ol'hreecling'l'
r 'Wlr:rl rrrr'llrc lrPPlrrcrrI liutcliorts tll'tlrc vlritlrrs lirt'ms ol'aggression'l'
t '\\lrrt lr rrrtlrr rrlrr;rl rlrtts;slr,r1'\\.\'- e r)r'ornllcrs: I'csitlcttt tlt'itttrtttlcr']'
' l','.ttt t t",'. t;tlt'rt'lltlr'rl lo ltotl\ r'r,''''
r' I ),rt', lltt'1.'r,'1,'l .tl'l'l(""'l()ll \,ll \ \\ tllr t lt:rlt1','t,ll l)()l)lllilll()ll (l('llsil\".)'
103
DILENEATION OF RESEARCH
:I
I
i
(2) (4)
When/Where
Exogenous (6,8)
strmull
Positive feedback
l ---t-- 
_-r-\i\
'-i--> Behavior "'.
+ Behavior -)What
Who/How
(4) (7)
Fig. 5. t The application of the model for a behavioral act to Crump's ( l98B) study of
aggression in harlequin liogs. The numbers in parentheses reler to 
questions
addressecl by Crump (see text for explanation)'
z Are subaclult (less than I year) males and adult males aggressive towards
each other'l If so does success rate vary with age'?'
8 '[s aggression related to the availability of prey in the habitat'/'
Crump's research objectives were to answer these research questions' 
Her research
hypotheses (i.e. what she believed woulcl be the answers to the questions) 
were based
on her reconnaissance observations and review of the literature (Chapter 4)' Her
research questions and hypotheses then lecl to statistical hypotheses (chapter 
1l),
the research clesign (Chapter 6), and a consideration of which factors to measure
and manipulate (see Chapters 6 and 7). These factors inclucled sampling 
arthropod
populations, observing natural aggression, ancl placing 'intruder' frogs near 
resi-
dent frogs (called 'originals'because she couldn't document their previc'rt-ts 
activity)'
Crump then proceeded with data collection (Chapters 8 and 9). data analysis
(Chapters l lto l7) an<l her interpretation of the results (Chapter ltJ)'
6 Design of research
6.I DESCRIPTION VERSUS EXPERIMENTATION
The dichotomy of description versus experimentation was introduced in Chapter I
and will be expanded on in this chapter. Also, reconnaissance observations were
previously discussed (Chapter 4) as a means of gathering background inlormation
about an animal (group or species) before designing a research project.
Reconnaisance observations help not only in formulating questions and defining
objectives, but also in determining what aspects of behavior can be measured, what
manipulations are leasible, and the degree of variability that is to be expected. These
initial observations occur at Level C in the Ethological Approach (Fig. 1.6); they
nlay occur before, or simultaneously with, delineation of research (Chapter 5). Once
the research has been delineated, it must be designed (Level D), and an approach
(description or experimentation) selected (Level E).
Descriptive studies usually involve observations under natural conditions since
we want to describe normal behavior; therefore, in the first edition of this book I
referred to descriptive studies as naturalistic observation (see Chapter I ), and I con-
trasted those with experimental manipulation; this is the same dichotomy used by
Martin and Bateson (1986). [n contrast, I am now convinced that the clearest and
rrrost uselul primary dichotomy should be between describing behavior (de,sc'riptive
rc,seurt'h) and testing one or more hypotheses (experintental reseort'lt). Experiments
rrre f urther divided into Mensurutive and Manipulutive, which are the observational
rrnd experimental approaches, respectively, of Martin and Bateson ( 1986). My defi-
nition ol an experiment, a test of a hypothesis, is the same as that given by Medawar
( 1960). The division of experiments into two types, mensurative and manipulative,
lirllows Hurlbert ( 1984).
Iloth rlcscriptivc and experimental research should include quantification, but
tlrurntification antl statistical analysis must not become the overlords of good-
tlrrlrlity obscrvlrtion. Sclcctcd examples quantifying descriptions of behavior are
prcscnlctl in ( 'lrrrptcr 10. Sonrctinres initial observations are difficult to quantify, but
IIrr'ir r,';rIrrt' is not rrcccssirrily gr-ca1ly climinishccl.
Norr;rtl;r1,s, rt is rcglrt'tlctl lrs tnotlcrtt to sct cxpcritncntation above
lll'l l,l;:i::,,"',1,'1.'il:l:ll':1,,";lll :iill"',l"llll,ll,ii:;i,l ;'il:",':lJ:.: iil;:l:HIill,,
v (3)
whv
Consequences'-) Feedforward
(Contingencies)
t5 -_-_!,]_ - __-.,,/'
Negative feedback
(G+E+D+(A+P)
Endogenous
106 DESIGN OF RESEARCH
to lorget that description is the foundation of all science. I do not rnean
to question the value of experiments, but observation must come first, in
order to generate qr-restions fbr experirnentation to answer. The
emphasis on blind, quantitative experimentation without prior
observation is based on the erroneous assumption that scientists already
know the questions to ask about the natural world. A theoretical
interest and patience are not the sole qualificatiorls for arriving at the
principles that govern the patterns of social behavior in higher animals.
That aim can be achieved only by those of us whose attention is riveted
on the behavior of our animal subjects because of the great pleasure we,
amateurs and dilettantes. take in our workl I Loretr:, l99l :7 J
Descriptive research involves observing and describing the behavior of anirnals
as it occurs naturally with as little human intrusion as possible. Naturalistic obser-
vation does not have to be conducted in the wild. Often an environment can be
created in the laboratory (e.g. for insects or fish) or captivity which closely approxi-
rnates the naturalliabitat of the animal. Gibbons et ul. (1992) discuss the design and
use of naturalistic environments in captivity for animal behavior research; they
include a timely and relevant discussion about concerns for animal wellare and reg-
ulations (also see AppendicesC and D;.
Description was the approach used by Tinbergen in his initial scientific study of
herring gulls (Zaru$ urgcntotrr^i), building on informal observations made through-
out the earlier years of his life.
Throughout the years of my boyhood watching the life in the large
gullery rvas complete happiness . . . watching the snow-white birds
soaring high up in the blue sky . . . It was this sentiment that sent me
back to the gulls in later yezlrs, when I returnecl with a matured scientific
interest. intent on exploririg the secrets of their community lif-e.
I T itrltt,rga n, I 960b :.r i i i J
Tinbergen's initial objective could be stated as: To describe the indivirlual behavior.
social beliavior and social organization of herring gulls living in a colony. Later, his
long-term studies evolved into experimental and comparative stuclies corrtluctecl by
himself and his students (Tinbergen. 1973).
Descriptive research involving naturalistic observation was thc basic irppnrirclr
usecl by Kruuk (1972 5) in his study of the spottcd hyena (('r'ttt'ttttt crrt<'ttttrl in tlrc
Serengeti National Park. T'he approach is reflectccl in the behuvionrl rlrrcstiorrs lre
asked:
lttttl ltrlrt' tloes I lris ('()nrl)irtt' tr r( lr
tlo lltr".r' ( ()l)lltiltt' tr tllt lltr' lt't'rltttl
VARIABLES
101
: How are the cluestions in t ancl 2 related,l
Description using naturalistic observation was the approach used by Nice (1937,
1943) in her stLrdy of song sparrows, Evans (1957) in his stuclies ol wasps, Geist(1971) in his study of mountain sheep, Schaller (1972, lg73)in his studies of-the
mountain gorilra and African rion, and Darri, go93r)in his study of red deer.
Altliough experintentation (discussed in Chapter. 7) and clescription represent a
dichotorny, they also complement each other. and most Iong-term research programs
oscillate between the two approaches (Tinbergen l9-51 ). Menzel (1969)6iscussed therole of the two approaches in primate stuclies (additional cliscussi,n is lbund in
Mason 1968); note that he usecl the term 'naturalistic'instead of descriptive.
I am, iti fact' convincecl that nzrturalistic and experimental studies can be
compatible with each other; that their respective methods can be applie<l
to any situation (instead of being linkecl to a given situation such as
laboratory or field); that both types of inlormation are necessary to a
meanin-ef ul general science of primate behavior; that any sharp.liuirion
between naturaristic ancl expe.rnentar methodorogy is not onry
undesirable but impossible; and that, finally. clisputes as to which
method .r situation is intrinsicaily best are nonsensicar.
[ )ltcn:cl t969;78 J
The further splitting of both clescriptive and experimental research into field anci
laboratory studies is cliscussed in the next cliapter; rvhichever approach is selected, aprescribed plan lor collection of clata is necessary. If experirnental research is
selected in order to test a hypothesis, then a carelul consideration ol variables and
experimentaI desigris is necessary.
(I.] VARIABI-ES
A vuriuhlc is a property that takes on difl'erent values (e.g. cluration of fbecling
botrts)' Trvo types of variable are involvecl in experinrental studies (also see cliscus-
sion in scction 6.-5):
Itrtlcp<'rrtl<'trt wriuhle'. the property that changes (or is manipulatecl: e.g.
Iiglrt lcvcl) .,cl is bericve<i (research hypothesis) to af-f ect the dependent
v'lr rirrblc (c.g. act ivity ).
Arr irtlcpcrrtlcrrt v:rri.brc is the presr.rmeci cause or-the clependent
rrrri;rlrlr'. rlrc prcstrrrrcrr cfrcct. 
IKt,rringer 1g64.-]9J
l)r'lttutlt'nl ytrtrtrltlr,-. tlrr..proltr.llyllrtrl isltclicvctl trtbCtrfl.CCtCcl bya
t lt;ttlt't'ttt lltt'ttttlt'Pt'lttlt'rrl r;rri;rlllr, ll rssr)t)tr.lit))r.st.:rltcrl lltcttrcitsrtrccl
r ,rt t,tlll(' ( )t ,t.,.,t,,ttr., I t;t t t.tl,lr.
109
108 DESIGN OF RESEARCH
Behavior will most often be treaterj as the dependent variable' However, 
it can be an
independent variable, as well (e.g. the effect of one animal's behavior on 
another's)'
The independent variable is generally designated as X and the dependent 
vari-
able as Y. Some relationship is presumed to exist between the two 
such that changes
in Ycan be predicted from changes in x. Correlations are often much more 
complex
than these linear correlations, but discussion of those correlations is beyond 
the
scope of this book.
Variables can be further divided into quuntitatit'e variables and clualitative 
vari-
ubles. Quantitative variables vary in amounts; qualitative 
variables vary rn kinds'
The type of dependent variable measured will, in part. determine the scale 
of mea-
surement you can use. For example, qualitative variables require a 
nominal scale'
whereas ordinal, interval, and ratio scales of measurement can be used 
with quanti-
tative variables (Chapter 8). The scale of ffIeasurenlent is important in selecting
appropriate statistical tests (Chapters 12-11 )'
Many experimental designs used by ethologists measure only one 
dependent
variable at a time: therefore, selection of the most appropriate dependent variable
(e.g. 'sitting'versus 'inactive') is very important (see cliscussion of behavior units
below). For example, Schleidt (1982) argues that among the many 
variables that can
be measured in a givel behavior pattern, those that are the most stereotyped 
are the
most useful in characterizing that behavior pattern. Selection of dependent 
vari-
able(s) to measure should be based on five factors:
. Validity- the variable should accurately reflect an effect oi the indepen-
dent variable and not some other extraneous variable(s) 
(see discussion
later in this chaPter)'
' Sensitivil.t'- the variable should have a high probability of showing an
eflectduetoachangeintheindependentvariable(s).
. Retiabilily , the variable chosen should provide the most consistent
results;those results should be repeatable'
. Distributirrt _it is valuable if the variable will produce normetlly distrib-
uted measurements; parametric statistics can normally only be applied
when this condition is met'
'Practic'alit1'_ ilseveraldependentvariablesemergeascancliclatcsrtfier
consideration of the four factors above, choose one Or mtlrc thltt itrc
easily measured;how much cost can you allbrd ilt tcrtl.ts ol'ctltrillltrcttt'
time and wages'/
All experirnents itre alst'r atltctetl by tttti's'tttt<'<' t'ttt'ittltl<"r'' 
'l'ltcsc ltte ttrttlt'sitt'tl
sorlrccs al'vitri.tion which cirn bilrs llre rcsrrlts. I'sycltolopists tt't'rr1'ttizt'tl tltt'tt
irrirl.lility ltl c.rrlnrl rrll llrt. r,lrrirrlrlcs lrrrtl t'oirrctl tltt' tr't ttt ittlt'tt'.'ttitt.ti trttrrtltlr'
('lirlttuttt. l()\X) ttt ltt't ottlll lot llll('lllitl ttol rlttt't lll' olrrt'lr:rlrlt' I'-\'t ll'rlrt1'tt 
tl
BEHAVIOR UNITS
processes that in turn alfect behavior; Kerlinger (1967:434) czrlls intervening vari-
ables 'in-the-head'variables. All potential sources ol undesired variation are nui-
sance variables (e.g. previous experience, perceptual ability). Nuisance variables can
be controlled in lbur ways:
t Eliminate the nuisance variable, if possible.
: Hold the nuisance variable constnnt lor all subjects.
r Irrclude the nuisance variable as one of the variables in the experimental
design.
+ Treat the effects of the nuisance variable statistically through the use of
covariance analysis (not considered in this book).
Besides nuisance variables there is also rutndentonit'intru,sion which occurs in all
experimental studies. Hurlbert (1984:192) defines nonclemonic intrtrsion as 'the
impingment of chance events on an experiment', such as weather changes. If these
intrusions do not aflect all samples equally, they will increase the experimental
error.
Examples of independent, clependent, and nuisance variables to be considered in
ethological research will be discr.rssed in the next chapter.
6.3 BEHAVIOR UNITS
Measurements in ethology are made on carefully selected, described, and defined
(in experiments) beliavior units. Whetheryou are conducting a descriptive study or
rrn experiment, one or more categories of behavior (e.9. reproductive behavior) will
lrc selected firr measurement. For example. you coulcl de.;t'rihe reproductive behav-
rrrt'itt species X. or tcst tlte hvpotltcsis that increasing temperature decreases the fre-
(lr.rcncy reproductive behaviors in species X. In either case. you must clearly
,lcscribe. and in experinrents define. the units of reproductive behavior that you will
r)rcirsure (e.g. courtship. mating. copulation, birth).
'[-hc choice of appropriate behavior units to be measured is at once one of the
rrrtrst inrportitnt antl clitllcult decisions to be made (Barlow 1977). As we shall see
l;rlcr in tlris chaptcr. this can be crucial to the validity of your research. The choice of
.u) irl)propriirtc bchavior unit is generally based on experience. tradition. logistics
,rrrtl irtlrritiott.
l:r'crr rvlrerc tlrcr-c is irgrccment about what general kind of description is
rrpproprirrtc. tlrcrc rrriry bc rlisugrecntcnt between 'lumpers'and 'splitters'
;rlrtrrr( rrlurl slrorrltl he corrrrtctl lrs lr ttttil ttf lttlttn'ittr lirr cltrantitative
l)ntl)(,sr's \\'lrt'r('\()lt)(' tlrllf lilltls. sonl:s trrrtl jorrrrrcvs. tltltct's tlrlly
I lltrt. 1977 I .\,\ I
DESIGN OF RESEARCH
6.3.1 Classification of behavior units
Behavioral units can be classifled in several ways (e.g' Bekoff, 
l9l9a; Hinde' 1966'
1970). In the report of his field stucly of social communication 
in rhesus monkeys'
S.A. Altmann ( 1965) stated that 'categorizing the units of social 
behavior involves
two major problems: when to split and when to lump'. He 
goes on to point out that
there are natural units, 'Thus, the splitting and lumping 
that one does is, ideally, a
reflection of the splitting and lumping that the animals do'' 
The aim in categorizing
behavior units is to be as objective as possible; however' 
as Fentress (1990) points
out, ethologists'personal perceptions, constructs and methods 
of categorization all
alfect their separation and recombination of behavior units 
from a stream of behav-
ior.
A reasonable approach to classilying behavior units is to work 
from the general
to the specific, using a scheme which closely follows the 
!evel of organization along
the species-individual dimension discussed in Chapter I (Figure l'l)' Throughout
thisbooklwillbeusingthelollowinghierarchyofcategories:
.Generalcategory:Thisisthebroadestlevelofclassification;Scottcalls
this category a'Type'(below; e'g' ugonistit')
.Behaviortype:AtypeofbehaviorwithinageneralCategory(e.g.uggres-
sion)
. Social Interaction:This follows part of Delgado and Delgado's scheme
(below; e.g. t'ha'sing)
. Behavior pattern: This refers to the linking of several behavioral acts
together into a reasonably predictable ancl stereotyped 
pattern; it coin-
cideswithpartofDelgacloandDelgado'sscheme(belowle.g.
threat chase)
.Behavioralact.Thisiseitheranelementofabehaviorpattern(e.g.tltcttt)
or a single act that normally occurs alone
. Component part: This is one portion of a behavioral act (e'g' burtitt'g
teeth duting threat)
one general classilication scheme was developed by J'P' Scott 
( 1950: Tahlc 6' I )'
He suggested that, 'The list provides a convenient guide lbr the 
clcscriptiort ol'
behavior in a new species, but in any particular case certain 
typcs [gcrtcrlrl clttc-
goriesl may be absent'(Scott, 1963:23)'
The generulc,ute96ricsancl /-)pt^r of behuviorsclcctctl lirr sttrtly will 
trc tlit'trttr'tl' irr
large part. by the qucstions being askerl irntl thc it1-rlttrrltclt 
sclcctt'tl' Itt tlt'st'ttPlirt'
stutlics wc usrrirlly gilthct' tlitt:r tltt IllllllY llcttctltl cltlctr'otit's 
ol l'rt'lt;tVtrtl' \\'llll(' \\('
.l.tcrt ttteltsttr.t.r.rr,l'r,u,ir,r rrrrirs *rtrrrrr rlrrl\ ,).('l\r)('()l lrt'lr;rrl()r tll 
('\l)('ttlll('tllitl
tt'st':ttt'lt
BEHAVIOR UN ITS
Table 6.1. Scott's (1950 ) c'la,ssification o/' behavior
General types of
adaptive behavior Deflnition
Ingestive
Investigative*
Shelter-seeking*
Eliminative
Sexual
Epimeleticx
Et-epimeletic*
Allelomimetic*
Agonistic
Eating and drinking
Exploring social, biological, and physical environment
Seeking out and coming to rest in the most favorable part
of the environment
Behavior associated with urination and defecation
Courtship and mating behavior
Giving care and attention
Soliciting care and attention
Doing the same thing, with some degree of mutual
stimulation
Any behavior associated with conflict, including fighting,
escaping, and freezing
Note:
Note that these are functional terms which must be supported by data before they
are applied in any particular study.
Behavior types can be lurther classified according to complexity and soc'ial inter-
ttt'tion by following a scheme prepared by Delgado and Delgado (1962). this scheme
was an outgrowth of their studies of modifications in the social behavior of
rnonkeys. Their classification of behavior units'evolved from a system of definition'
rtnd was used within the framework of an explanatory model of behavior which
they also developed. Briefly, their classification scheme is as follows:
A Simple behavior units
t Individual
(i) Stutit' or po,tturul units can be identifled by static relations (e.g. sleep-
ing alone)
(ii) D.rtrtuttic or gc.tturul"unilscan be clefined and identified only by a
sc(lucncc ol'spatial relations (e.g. climbing a wall)
lrl ltx'uli:ul involving only part of the system (e.g. moving legs)
tb) .qrttrrulitl involvirrg a change of position of the whole system
in rcltrtiorr lo its cnvinrrtntcnt (c.g. walking on ground)
'Sot'ilrl
(tl '\'lrrtrr (,'l' ttt,rltkt'Vs slt't'llittt'. t'tttllt;tt'ittl't'ltt'lt rllltCt')
( rr) /)t uruntr (r'l' ;t nto11l11'1 t lt;r',ttry, :rrrollrr'r )
112 DESIGN OF RESEARCH
Sirnple
bchavioral
units
Active
Passivc
Individual Static or 
postural 
5 Localized
L Dynamic or gcstural 
-l L Gcncralizcd
sociar _t il,ll:.,.
Complcx
behavioral
units
Simultaneous
Sequential
Syntactic
Roles
Fig. 6.1 Delgado and Delgado's (1962) scheme of classification of behavioral units.
B Complex behavior units
I Simultanetlus
2 Sequential
3 Syntactic - the significance of the behavioral unit may vary with context
4 Roles (e.g. groomer-groomed, threatener-threatened)
(i) At'tive
(ii) Pc.s.rruc
Delgado and Delgado's (1962) scheme of classification of behavior units is illus-
trated diagrammatically in Figure 6.1.
At the next level in the hierarchy, specific bcltuvior puttern,\ can be isolated. For
example, a duck can move (locornotion) from one place to another by using one of
lour behavior patterns: walking. swimming. diving, or flying. These patterns could
be broken down further according to social, spatial and temporal variables such as
flocking and height and speed ol flight.
The next level specifies hehuviorul ut't,t within a given behavior pattern. Firr
example, flying can be broken dowrr into the acts of taking ol1. flight ancl lancling.
Acts can be f urther classified rnto utrrtpt)nent purts. Taking olf can bc clividetl
into rnovements of various parts of the body (e.g. head. wings. lcgs), anatortricirl
structures (e.g. muscles and bones). and neurological activity. Str-rtly ol'thc intcr.nrrl.
physiological, component parts of behavior are beyond the scopc ol'tltis lrook.
however. several excellent ref'erences are available (c.g. ('anrhi. l9li-l: l:rvcrt. l()l'i0.
Guthrie. lc)80, l9tl7. Kantlcl. 1977).
[.,thologists slrtlrrlrl rto( corrccnltlrtc otrll'ott ltclurr,'iot rrrtils;rl llte p;rrlit trl;rt lt'rt'l
sclcclr'tl lirt irtlr'ltsivt'slrtrl\'; lltr'\'r'rrrt 1':rilr rrrlrliliott;tl rtnrlt'tsllrtrrltttl llrtottr'lt lltt'
l)l{}r'r'sr 0l 'l{}t rl',tlll' tll ;lll(l 'l,,, rl'\lll,' (rttl ltr)llt \(,. lttl tlll('lil( ll()ll', l(r ( ()llll)()ll('lll
BEHAVIOR UNITS
9OC tAL TNTERACTION
BEHAVIORAL ACT
COMPONENT PART
Fig 6 2 An observer fbcusin,e in and out between the sociar interactions, behavioral act
and conrponent parts ol a herring gulls,oblique Iong call(drawing by Dan
Thompson; based on Tinbergen, 1959, 1960b).
Pitrts of behavior (Figure 6.2). This is irnportarlt not only during reconnaissance
.bservations when you are deci<ling on the particular behavior units you want to
sttrcly' but also when you ilre trying to gain additonar insight into the causation orlirllction tlt' specific belravior patterns yon have been observing. Based on histlcscriptivc studies tll' great crested grebes (Podicep.s (ri.tt(ttu.t),conciucted almost a(crrtLrry ttgo. llLrxlcy (lt)6877, rel2rint of book published in l9l4) made suggestions
rr lriclr holtl tr-rrc lotliry.
' ' ' t|rttt ltitt.q ttl t ltttt' tlrrrrrlt'r.r ntust be adopted in order to work out the
t'xrrt'( nrerrrrirrl ol'caclt sc1-111r.atc bit of behaviour. Only when the general('()tll'\('.l cl'eltls ltlts llcctt ltltrgllly trirccd arrcl srlrtte hypothesis. h,r*ever
\:lJ'll(" lt;ttttt'tl t'rtttt't'l'ltitt! it irr tlrc w'rrlclrcr''s rrrintl. ciur thc ftnc shacles oflrt'lt;ttlrrttl l,',t',';lll\ lll(';rttinl lil lrirrr ll is irrrpossihlc trl nrlricc rlr rccrlrcl('\('lVllttttt' ;tlttl.111i'ttltt'tl rr)rr('l'('n('r;tl rrlt.rt l1,ts lrr.r.rt t,ltirtetlclttt lltcr,tltt,',rl ,rrr\ l,rr I lrr.lrl,lrr,rlt ,rl,l)t(.{ t;tl{.{l ll r: ()tl lln\ it(.(.(}ttnl llflfl I
lt3
1
rl
I
l4 DESIGN OF RESEARCH
would say. always begin by distunt watching; otherwise you will not be
able to see the wood for the trees.
In Figure 6.2, the observer is focusing in on the alerrmed herring gull described by
Tinbergen:
Some of these movements and postures are not dilficult even for the
human observer to appreciate, though the detection of most of them
requires careful study. There are a multitude of very slight movements,
most. if not all, of them characteristic of a special state of the bird. The
student of behavior is to a high degree dependent on his ability to see
and interpret such movements. [r'r the beginning, he will notice them
unconsciously. For instance. he will know very well on a particular'
occasion that a certain gull is alarmed. without realizing exactly that he
knows it. Upon more conscious analysis of his owll perception (an
important element in beliaviour study), he will notice that the alarmed
gull has a long neck. Still later, he will see another sign, the flattening of
the whole plurnage. which makes the bird look thinner. Upon stillcloser
study, he will see tliat tl-re eye of an alarmed bird has avery special
expression. due to the fact that it opens its eyes extremely wicle.
ITinbergen, 1960h.7 ]
6.3.2 Spatial and temporal aspects
In Chapters I and 2 we discussed the what, wlten, where, who, how and why ques-
tiorrs of beliavior. In this section. we are dealing specifically with the when and x'lrcre
questions. These two dimensions are inherent in all behaviors (Chapter 2: Figure
2.6); howeveq they may either be an important aspect of our research question. or
they may be ignored relative to other aspects (e.g. who, how). Exarnples of the study
of spatial and temporal patterns will be provided in Chapter 10.
Spatial and temporal parameters of behavior are usually relutit't' tlitncti.:'iort.:'.
This will become clearer as we consider the questions below, which focus l'rom the
general to specific spatial and ternporal dimensions.
I
2
3
4
5
(r
Spatial questions:
In what geograpliical location is the animalfound'l
In what habitat is it located'l
At what position (vertically and horizontally)'l
What is its location relative to other membcrs tll' its group or' poprrlirtiort'l
Howdoitsl-t"tovemcntsvitryt'clittiv'cttlwltct'ci((;trttl olltct'tttt'tttl'rr-'tsol tls
groLlp tlr ptlprrIation ) lr rc loclrIcrl'.)
llrlr.vtlollte nto'n't'tttcrrlsol ()n('l)irtlol lltr'lrotlvt'ottr'l:tlr'trilltttt,r\t'tttt'nls
ol olltt't lrotl\ Prrtls(r'1' sP:tlt;tlltllrr.r.'tttr.'ttlol lt'r'l tltlttttl'lot'ontols11s1;'t
BEHAVIOR UNITS
Temporal questions:
r At what ages do different behaviors appear i. the animar?
z When is the individual observed (year, month, day)l,
: How does its occupation of a particular location correlate with season
(e.g. migration)/
+ How does its behavior vary on a daily cycle?
s How is its daily activity broken up into clifferent generalcategories of
behavior or behavior types (i.e. time budget)?
o What is the duration of occurrences of specific behavior acts (or bouts of
behavior)?
z What is the relative timing of behavioral acts in a behavior pattern (e.g.
synchronization of leg movements during locomotion)?
s Wrat is the relative timing of different component parts during a behav-
ioral act (e.g. rnovements of parts of the body during threat),/
It can be seen that the spatial and temporal questions nrerged together in
Questions 6 and 7. These two dimensions are interrelated ancl separated by the
ethologist either because of the emphasis of the research question(s), or lor conve-
nience and efficiency. Spatial aspects are an integral part of Drummond,s Domains
of Regularity (described below).
6.-3.3 Descriptions and definitions of behavior units
Once behavior units are chosen lbr study they rnust be clearly described (Chapter 4),
ittrd especially fbr experimental studies they must be cleerrly cteftnect.Clear and com-
Plete clesct'iptions are rrot only necessary lor;uar research, but they also provide a,
Itccurate picture of the behavior fbr other researchers; this sometimes results in the
Published descriptions of behaviors being more complete than the actual criteria
trsecl by the researcher to determine when a behavior unit is occurring.
Behavior units rtsed in experimental sludies are generally operatittrrutt,r; deftncd
(c'g' Giles itnd Hr-rtttinglord. 1984; see below) in order to increasc reliability (both
ilttrit- ancl itrtcr-obscrver). For example, we can say that when behavioral acts x
'rrttl l'occLlr togctltct. lvc will rec6rd an occurrence of behavior pattern Z;thatis,
l'cltitrior Prttlct'tl Z is operationally clelined as the simultaneous occurrence of
lrelt:tviot'itl ltcls .\'ltrltl r. we may have chosen to operationally define behavior
lr:tltct'tt '/ ittl lris lv:ty lirt'5;cvgt',1 r'cAS()ns: l. we consicler them the.most important,
lrt'ltrtrirrtrtl rlt'ls itt lreltltr'iot'P:rt(cl'rr /..2. .\'itntl l'arc thc most easily clbserved
l,r'lutr rt,1 ;,,'1s ilr lrt'lt;rviol 11;sllcrn ,/. l. .\ :rrrtl ). lrr.c lhc lclrsl trrbilrirrilV clcfinccl
;tr'ls. :rrrrl .l llrt. :lrlrrlliul(.()lt\ ()(.(.utt(.n(.(. ol \ ;rrrrl ) lr;rs lree rr trsctl lts lltc ct.ilcl.iort
I r\ r rl ltr't I r.',r',r I t lrt.r .,
ll5
I
ill
r l6 DESIGN OF RESEARCH
Table 6.2. S0nte o/ the behtrviors ret'ortlad during tha 
pike tests ttntl heron tests of'
unti-pretltttorbeltttt,iorinstic,klebttcks(Gasterosteusaculeatus)
Behavior Definition
BEHAVIOR UNITS
apparent that the identity of each one resides in certain regularities,
ties which are common to all instances, and that the regularities lie
number of domains'. as lollows:
t Lotution of the animal in relation to its environment (see
z Orientution of the animal to the environment (see section
i
117
in those proper-
within a limited
below)
10.2.1" on dis-
Position in tunk
* At surface
* At bottom
* In weed
* Open water
Locontotittn 4'Pa
* Sneaky swimming
Jerky swimming
* Nornral swimming
* still
Remaining at tl-re water surface tilr more than 0'5 
s
Laying upon the substrate, usually still' fore more 
than 0'5 s
Remaining within artificial weecl clump provided 
in
experinlental tank, tbr more than 0'5 s
Remaining at least I cm away from the water surlace'
substrate or weed clump for more than 0'5 s
Smooth swimming usually along the bottom using 
caudal
anil pectoral fins with dorsttl anrJ ventral spines 
lowered
Fast agitated swin-rming using pectoral hns typified 
by
abrupt stoPPing and starting
Slow bouts ot'pectoral swimming with frequent 
pauses and
stopPages
Remaining stationary in any part of the experimental 
tank
lor more than 0.5 s
Barrage balloon Slow vertical ascent to water surface with 
little or no fin
movements,facilitated by swim bladder expansion
* Jump awaY A rapid bocly flexure and stroke 
of the caudal fin causing a
fast 'leap'through the water usually to a place 
of cover
plays)
Plry.sic'ul topogruphy of the animal (see section 10.2. 1, on displays)
Intrin.sic properties of the animal (e.g. changes in color, temperature, and
electrical and chemical properties)
s Plt.vsit'ul e./l'act.s induced in the environment by the anirnal (see section 7. I )
6..1.3a States ancl events
Determining the exact duration of a behavior is often very difficult, not because the
instrumentation is not available, but rather we olten do not have the necessary skill
and observational experience; tliat is, it is often difficult to detenline when a behav-
ior begins and ends. Nevertheless, alter observing animals lor only a short period of
time it becomes obvious that most behaviors can be divided into two categories
based on their relative duration (Altmann, 1914):
' Stute the behavior an individual, or group, is engaged in; an ongoing
behavior (e.9. a robin flying); a behavior you can time with a stopwatch; a
tluration nrcuningf u/ behavior (Sackett, 1978).
' Event a change of states (e.9. a robin taking offl; it approaches an
instantaneous occurrence that happerrs so fast that you just count its
occurrence: a tnonlentart' behavior (Sackett, I 978).
For example, in Table 6.2 'sneaky swimming'would be a state, but Jump away'
could be considered an event. Likewise. 'normzrl swimming' (state) can be inter-
rupted with fiequent'pauses' (events).
Throughout an animal's lile it is constantly cycling through states and events. In
stuclying etrtirnal behavior we are merely sampling selected states and events. either
lrs they occlu-'nuturally'ol'are induced by the experimenter.
Evetrts itntl slitlcs can be measured in various ways. The most frequent measure-
rrrcnts arc listctl in'lhblc (r.3.
h.t.th Iiltrtt.t
Iltr'lr't nt l,t,ults 1'r.',,..',',llr :r1l;llit'rl lo l lr rt'Pt'lrlivt'ot't'uncncc rll'tltc s:rtttc bclr:rv-
l()t;tl;t( l(r'1, ;t lro1ll 1,1 |r..'r. kltt1') ot t ir rr'l;rltrt'l\ ',lr'rr'oltllt'rlst't;il('n('('ol llr'lt;tvirlts
Note:
* Behaviors inclr"rded in principal component analyses 
(see chapter l6)'
Sourca;From Giles and Hr,rntingford 
( 1984)' Copyrighted by Bailliere Tindall'
It is obvious that we cannot measure what we cannot define' 
It is eqtrally
truethattlrei,vaywe<lefineandrecorclbelravioralelementsrvillbc
affecteclbythetypesofmeasurementwewishtosrtbsecllrcrrtlyirpl.llyttl
them. 
/ - 
f Httt t ttnd tlutt' l<)70 'l'j I
Asanexanrple.Table6.2listssonreofthetlperatitlritrltlc(irrititltrsttsctlllv(iilcs
ancl Huntinglbrd (1gg4) i. their str.rdy.f tlie a,ti-prcclut.r 
hcr*vi-r'.r'srickrcb:re ks
in response to Pike ancl herons'
whcn tlclinirrg llcltitvitlr tttti(s lirI cr1'rct itttcrttlrl sttttlics' 
otte sllottltl t'ottttrlt't
r)r.rrrrrrrrr.tr.s ( r()ri r\ r)tt,trtitt.:, ttr rir,.tlttrtr.itt'. r)rrrrrrrrr.rr.r 
( r()l"i r.\.(r) sllrtt's rlr;rl 'll
\\'('('\ltlllttlt'lllt'rt't\ lrtt';ttl l;tlt1"' t'' Iltt'ttt)lll('llil 
tt't':tttlt'tl;ts lrt'ltltrllrl |illlt'ttt" tl t"
118 DESIGN OF RESEARCH
Table 6.3. Meusttre's.f ttr stolc'\ uncl events
Type of measure Definition
Usual apPlication
Total frequencY
Partial frequencY
Rate
Duration
Number of occurrences Per samPle
unit
Unknown Percentage of total
occurrences Per samPle unit
Number of occurrences per unit time
Amount of time Per behavior unit
Events, states
Events, states
Events
States
that occur i. a behavior pattern (e.g. a courtship-display bout). Analysis of 
the
latter type of bout will be considered in Chapter 15'
There are two criteria (qualitative and quantitative) lor defining 
bouts of behav-
ior:
t Clrunge in heltavior'. 'If more than one behaviour is being observed' then a
bout of'one behaviour is said to end when a different type 
of behaviour
begins' (Machlis 191 1 
"9)' 
For exatnple:
tsout: a consecutive series of songs which may vary in minor 
ways but
neverthelessconformstoaparticularsongtype.IMulligun'1963..2761
2 Itttert,uls bettt,een ()(cLtrrence.y. A criterion interval X, is chosen to sep2lrate
one bout from anotl-rer. Al1 intervals equal to or greater 
than x ,are classi-
fied as between bout intervals aucl all those less than x, as 
within btlut
intervals'(Machlis l9l'7 '9)' For example:
If rnouth activites of the same kind fbllowed each other in intervals of
lesstliiinl6seconcls.tlreyareconsideredtobea.bor.rt'.
I Hciligcnbcrg' 1965' 161 I
Figure 6.3 illustrates how the usc of clilferent criteria allects the arralysis 
ol'
bouts. Behavior A appears to occur in discrete bouts that seem 
obvitltts ll-our tltc
record. Both bout criteria (above) could be applied equally 
well to tlclining thcsc
obvious bouts. Behavior B. however, will fall differently itittl 
b.uts dcpcritlirrg.tt tltt'
criterion chosen. If we choose criterion I then therc are twtl boltts' Il'wc 
trsc cIilc-
rion 2 with a bout criterion interval (Bcl) of 30 scconcls. tltcrt tltct'c 
ltt'c lltl'cu bottls'
if we use a BCI of l0 secotrcls thcn thcrc arc fivc bottts'
Scptrrati...l-ir str.crrrrr rll'trclr:rvior irrlo borrls sltottltl tellt't't rvllltl 
ur'('(rllsl(l('l
Irl.lltrrll.rr.ilrlc lirr tlre sPeCies \t'(' ill't. sttttlvittl' l'ot e rltttrPlt'. 
l{t)st'lll)llllll ( lt) /i"i ) (ll\
t.ttsst.tl lrr'rr tlttttt.ttsir}ll\ ()l ltttttllttt lrr'lt;tr,tt,r tr,ltit'lt llt. li,tttttl 
ttst.l ttl ttt tlt'ltttt.:ttlttl'
BEHAVIOR UNITS
Fig. 6.3 Hypothetical record from an event recorder for behavioral events A and B. Time
marked every l0 seconds. See text tbr explanation.
bouts: l. a change in the level (intensity) of motor output; and2. change in orienta-
tion. A bout criterion interval should only be designated alter the observer has
become acquainted with the species'behavior.
After becoming familiar with the social behaviors of laboratory rats. Grant and
Mackintosh (1963) selected three seconds as the maximum amount of time that
could elapse between behavioral acts of the same rat in order to consider them part
of the same sequence (bout). Dane and Van der Kloot (1964) studied inter-individ-
tral courtship display sequences in groups of male goldeneye ducks (Buc'eplrulu clan-
qulu). From their observations, they set a maximurn time of five seconds which
could elapse between displays of two ducks in order to consider them a
stimulus response sequence (bout).
A more objective method of defining the BCI is to examine the fiequency his-
logram of intervals between behaviors, or the log survivorship curve (Figure 6.4).
I hc log survivorship curve describes the probability of an behavioral act occurring
rclative to the time elapsed since the last act. When behaviors occur in bouts, the
slopre ol the curve is steep initially and then becomes gradual as the intervals
lerrgthen. The curve is generally considered to break into two portions: l. a steep
'.t'ction of'short within-bourt intervals and 2. a gradual section of longer between-
lrorrt intcrvals. Thc break point between the steep and gradual sections of the curve
,;rrr trsrrally bc approxin-rated by visually inspecting the curve (Slater 1974) (Figure
{r 5).
Ilrc grirrlual portion of' the'curve can usually be fitted with a straight line,
rrrrrkirrg, it rrrr cxponcrrtirrl l'unction. Machlis (19'71'.14) devised a procedure'to deter-
rrrrrrr'llrc rrrlrrirnrrrrr nurrrbcr rll'long intervatls which cnn be incorporated into the
t;rrl" ol llrt'('ur\e brrt strll hirvc this tail lit reasonably well to an exponential func-
rr,n' l lris lrror irlr's ir \e rv objcctivc pnrccrlur-c lirr dclrning the bout criterion inter-
r.rl \\/lrr'rr \()ur l)lur:u v irtlr'tt'sl is irr tlrc ltcltrtvirlt'which ()ccurs itt thc stitrt ttl bt.lttts.
',l,rlr't ;llrrl I t':lt'r (1')i-i 'l r('('()nril('n(l st'lt't'l rrr1' lr linrr' inltt'r.:rl sliglrlly lrtngct'tltitn
tlr,rl ,rl rrlrr, lr llr,',,1,)|t'r lr;url'(", nr()\l r;rlrr(ll\ W'lrr'rr \()ut l)nnllrY int('r('\l rs irt llte
I
I t9
120 DESIGN OFRESEARCH
lnterval length (5 x 100)
Fig. (r.4 Bsuts 6l- pccks by ('obb's Ilighllrrrtl rrrrrlc clricks ltt ltttlics'llrrl Pirls. I lt't1ttt'ttt 1
Itistogftttrtsol'intelvtrls l)el$('crr llt'tks.,tllrl l,,r'\tlt\l\(,tsltiIttttrt's W lll
r.rpr'ri1rt'trl I rrslt1';r:itry,l,'rrlrilr'pttr (rr \()). W l\' ('\l)('lllll('lll'l rr.,ttr1"t "ttt1'lt'
*lttlr.grrrr {rr '(t) \\'\\' ( \l)('unt('nl lt.llll'lrtt, rrlltlt'1rttt. (rt l')) (lr('lll i\l't( lrll '
l,)// lll,ltr./)
BEHAVIOR UNITS
^oro.\.
\
\
200 400 600
Gap length (sec)
Fig. 6.5 Log survivor lunctions fbr intervals between pecks at lbocl for three birds. Each
point gives the number of intervals longer than gap length shown on the abscissa.
Arrows indicate the point chosen lor bout definition for each bird (from Slater,
1974).
time allocated to dilferent behaviors (i.e. time budget), Slater and Lester (1982) rec-
()mmend selecting the time interval at which the slope changes most rapidly in order
to recluce the number of within and between bout intervals being assigned to the
\\'r()ng category.
When long-terrn records of behavior are examined, bouts may be for"rnd clus-
tcrccl into 'super-bouts' (Machlis. l97l). The log survivorship curve may then be a
, orr.rposite of three types of bout intervals: L the initial steep portion of within-
lrout intervals; 2. the intermediate slope reflecting between-bollt intervals; and 3.
tlrc very gradr-ral slope representing between-cluster intervals (Figure 6.6). The
strper-bouts' may reflect diurnal rhythms, such as morning and evening feeding
pt'r'iotls. Wc tltcn have a hierarchy of behavior units as in Figure 6.7.
Sibly cl ul. (1990) rccommencl using log frequency rather than log survivorship
( ur\cs lirr splitting bchavioral ifcts into bor"rts. The data points in log frequency
t U r \ cS lr rc irrtlcltcrrtlcn t o l' cach other so that non-linear curve-fitting procedures can
1,,';rpPlrcrl rrrrtl ;rrrrrlysis ol'variance tests can be used to determine whetlier the
I ,,'lr;n ior ;rl ;rt'ls ir e l)r()l)crly split into bouts. Since tliis is a more complex procedure,
"rlrlv 
r'l (tl ll(y)ll) .lrorrltl l)e c()nsullctl lir'1hc rrpplicablc nrcthocls. as well zts how to
,r;rplr lr';rsl \(lu;rrt'st'slinlrlr'slollte lortnul:r ptrrvttlcrl bySlltcrttrtd Lcslct'(1982).
llroottt (l()/())r';rrr lri't'ortsttllt'tl l()r nr('lltorls l() iulirlVzt'sct'ics ol':t ltltltvirlr ttt
rrlrrr lr l)r'rrorltr rlt r',',rr',lrt'r'lt',1 (t,' rlttllrrrr',) Ilrt",r'tnt'lltorls tnt'ltttlr'rtttlo-t'onel:t-
t2l
oS r
Ea
=CCG)
L-
5r;
s
oc
=
o
LL
o: )R.Z-1E-
=Ctro)LJ
a*(J6
s
(J
C
q)
f
U
o)
LL
100
80
60
a
3 10o
o)
o
0)
_o
E
fz
50
30
l.uro
lnterval length (5 x 100)
BEHAVIOR UN ITS
DESIGN OF RESEARCH
lnterval length
i;::":i;
n
il llll llll llll il ffi lll
Bout cluster
Evening feeding period
A
()
c
o)
f
o)
o
.z
o
l
E
f()
. Moves to
Fanother mea<
B
o
o)
o
o)
o)
.z
(o
)
E)
(J
C
Within-bout
intervals
(State l)
Between-cluster
intervals
(State lll)
llll
r-1
ilil
r-l
ilillllll ililll
Model for the log survivorship curve based on the assumptitlrt tltitt tltc ittlct'vrrls
between pecks represent three clifferent states withirl thc chick ((')lntl llrll tlrcse
intervals are Poisson generatetl. Such intcrvals will hc cx1'rottcttlrlrllv tlistttlrttletl
ancl will havc log survivrtrship lirnctiorts its sltowtt ilr (lt).'l ltc c,rttlP,'stlt''rl lltt'st'
distributions is showtr in (A)(lirttt Mttclrlis. l()77)'
lnterval length
O"rr-ffi
-nt ntm
bites
Frg. 6.7 Hypotlretical record ol a portic'rn of an elk's spring feeding pattern broken into a
f'eeding period. super bouts, bouts and bites. Super bout:time in meadow spent
primarily in feeding; bout-time with head bent to ground biting vegetation or
seeking other clumps, separatecl by head-raised posture.
tion (e.g. Roberts, 1994) and Fourier-type spectral analysis. The analysis of bouts of
a group of different behaviors is discussed in detail in Haccou and Meelis (1992).
6.3.4 Number of behavioral units to measure
Selection of the number of behavioral units to measure will be alfected by several
llrctors. The ntitrintarr number will be dictated by a determination of what units are
inrportant in answering the research question; that is, what is necessary for a valid
tcst of the hypothesis. The ntaxintunt number will be determined by the experimen-
trrl design, sampling method. data collection procedure (i.e. equipment), the ability
rrnd experience of the observer, and logistics. Hutt and Hutt (1970) concluded that
.rn observer is unable to cope reliably with more than 15 separate behaviors.
llowever, many examples can be lound in the literature where more than 15 behav-
ror'5 ]1sys been recorclecl; nevertheless, reliability (Chapter 8) rnay decrease as the
rrrrrnber of behavioral units measured increases.
Logistics may restrict the number of behaviors that a single observer can
rncirslrre. Behaviors of'interest may be distributed throughout a24h period such
tlnrt a single observer wcluld have to make observations continuously; ar-r efficient, if
rrot impossible proposition if extended over several days. In these situations, several
,,bscrvcrs irrc rcsponsiblc lirr recording data during different periods of the 24h
lrr'riorl. l.ikeu,isc. thc bchaviors ol interest might be spread out spatiallysucli that no
',rrrglc obscr''u'cr crn rcc()r'(l all the data. For example, Krebs (1974) used three
{)l)\,t. r'\'crs in lris sltrrly ol'colottiitl nesting and social feeding in great blue herons in
,,rrlr'r lolrrllrcr t'orrrplclclrrrtl irccurirtctlataot-tl'eedingflightscluringthepeakof the
1t'rl11, lrt'l iorl
( )nt'olrst'rr('r \\;rs slrrtiont'tl irr tlre ohsr.'r.r,';rtitlrr lritlc in thc colotty rtntl
\\,r', rr t:rrll,, r',rttl;tr'l tt tllt rt \('('()tt(l ollrt't \'('t ()tt lltr'sltol'r' littr'r'ltlsr'l<l
Fig.6.6
N)s
an
2
z
'i,1
rn
a
rn
-
f
i+Ei !&i.ii,= =Eii€[tgu-i?=i?
i{1il 
?lillEi li3i iEgBE 
ail?iii 
, 
zril1i,
ziia : -ei=a::i ;ii* ur: ;5 i|Z*'*ii ?i;;ei
=ziz; lrg iiE:ai 
ue;ii*Ei-gi +i;;aI
t=7_, ilglgtf i i;e::ra?3 tfiai
7zi1 ig? :i'i € lErElEiEi il;la
,=1; 
lie:E ? e Eig?Eig ii ii3Eii
Threats to external validity
St.it istical
:i {rissir)n
Selection
ll.1sL's
- \rtrition
il ..:.':", \nr erent (other than tlie intervention)
\ni change over time that may result from
processes li'ithin the subject
\n1,'change that may be attributed to the
r ::, i, i,,,, e n t ar i o n i:*,l:i:.:::1ffi','L:1,iil1l';he measuring
instrument or assessment procedure over
timp
Any change from one assessment occasion to
another that might be due to a reversion of
scores toward the mean
Any diff-erences between groups that are due
to the assignment of subjects to groups
Any change in overall scores
l. Generality across
subjects
2. Generality across
settings
3. Generality across
response measures
4. Generality across
times
5. Generality across
behavior change
agents
6. Pretest sensitization
7. Multiple-treatment
interference
The extent to which the results can be
extended to subjects whose
characteristics may dilfer fiom those
included in the investigation
The extent to which the results extend tcr
other situations
The extent to which the results extend to
behaviors not included in the
experiment
The extent to which the results extend
beyond the times that the invervention
is in eflect
The extent to which the intervention
etfects can be extended to other
researchers
The possibility that assessing the
subjects before treatment in some way
sensitizes them to the intervention that
lollows
The results may only apply to other
subjects who experience both of the
treatments in the same way or in the
same order
:. DrtTusion of Occurs when the intervention is inadvertently
treatment provided to part or all of the control group
or at the times when teatment should not be
in eflect.
Sourcc: Adapted and abridged from Kazdin (1982). Coyrighted by 1982 Oxford University Press. Inc. Reprinted by permission.
126 DESIGN OF RESEARCH
designs (below)and statistical proceclures (Chapters ll-17) before setting out to
collect data. However, il-you are uncomfbrtable with ygur choices of experimental
clesign and statistical tests, you shoulcl review therr-r with a statistician'
. . . to write of the 'experimenter'and the 'statistician' as though they
are separate persons is often convenient; the one is concerned with
undertaking a piece of research comprehensively and accurately yet with
reasonable economy of tirne and materials, the other is to provide
technical advice and assistance on quantitative aspects both in 
planning
and in interpretation . . . the statistician can produce good designs only
ifheunderstandssomethingoftheparticrrlarfieldofresearch,andthe
experimenter will receive better help if he knows the general principles
of design and statistical analysis. Indeed. the two roles can be combined
when an experimenter with a little mathematical knowledge is prepared
tolearnenoughtheoryofdesigntobeabletodesignhisown
experiments. I FinneY' 1960' -] l
As Finney has stated above, just as the researcher relies on the statistician' 
the
statistician relies on the researcher to provide the proper data.
The discussions of experimental designs and sttttistical analysis in this book are
introductory and cLlrsory. The material represents what I believe to be the 
minimum
knowledge ethologists should have in order to cou<luct their research 
with insight and
logic. [t is meant to supplement, not substitute for, consultation with a 
biometrician'
65 BASIC EXPERIMENTAL DESIGNS
Experimental designs are protocols for measuring and/or manipulating indepen-
dent variables in such a way that their singular or combined eflects on 
the behavior
being studied (<lependent variable) can be determined. Choice of the 
proper experi-
mental design is based on knowledge of the: l. objectives of the research; 2' 
hypoth-
esis to be tested; 3. feasibility of gathering various types of data; 4' types ol'
experimental designs available and their relative attributes of power and efficiency'
The selection of an appropriate statistical test (Chapters 12 11) is based' in large
parrt, on the exPerimental design.
6.5.1 variables, samples, treatments, blocks, individuals and mcasurcmcnts
There are six terms that are necessalry to understancl in orclcr 1o lltriltl lll)l)r()l)liirte
experimental clesigns ancl apply valicl statistical tcsts. Tlrc ttotrttiott:ttttl 
tle lirritiotts I
Llse 
^re 
cirsy t6 updcrstuntl unrl rcnrcnrbcr'. btrt tlrcy rrrlry tlil'li'r ll.ttt titItt't lt'rts Iltt'
Ic'.rs irr.e tlclincrl hclor.l,irr tlrt, lricrlrrc'lrr;rl llrurr('t irr r'rltit'll lltt'v;ttt'ltPPlit'tl to
('\lx'lilll('lllltltlt'si1'tts(tt'lt't lt' l;tltlt'() \):ltttlstltltslit';tllt'slr
BASIC EXPERIMENTAL DESIGN 127
Independent variable(s) (A,8. . .)
An intlepenclent utriable is an environmental factor that l-ras diflerent discrete or
continuous values; we study the effect that different values of one, or more, indepen-
dent variables (1,8...)have on one, or more, dependent vuriables (behavior units).
The independent variable in Table 6.5 is the natural time o.f day, and two values of
time of day were selected for determining their ellects on house rnice activity: noon
(l I ) and midnight (A2).Table 6.5 illustrates a mensurative experiment in which the
two values of the independent variable were measured.
In manipulative experiments where we artificially change the independent vari-
ables, the manipulations are called trcotment,e. For example, il' the experiment in
Table 6.5 had been conducted in the laboratory and the photoperiod had been
manipulated to create artificial noon and midnight, those two values of time of day
would be considered treatments.
Sample(s) (Sr,, Srr. . .i S,, Sr, . . .)
A ^sumple is a set of measurements of the dependent vuriable (behuvior unit) on a
number of individuals. Each value of the independent variable, whose effects we are
studying, is indicated by a nun-rber ( 1,2 . . . tl).For example. in Table 6.5, one sample
(,t,,) is taken at Noon (Al), and one sample (Sr2) is taken at midnight (A2). Each
Srr rrr ple contains eight nte u sur e nle n t,\ .
ln experimental designs where we take two, or more, samples from the same
lrrlLre of the independent variable. those multiple samples are called replications.ln
the majority of ethological studies we take only one sample tl'om each value of the
rrrtlcpendent variable; therefore, we commonly refer to the number of samples,
rrllter than the number of values of the independent variable, when discussing
('\l)crir.nental designs and statistical tests.
Block(s) (Br... B,)
llltrcks irt'c lrscd in a rondotni:cd hlock design to control lor the eflects of a nuisance
r;rrirrhlc; tlte l'at'iouslevclsorczttegoriesof thatvariablearedenotedbyB,., .,,. In
l:rlrlc (r..5. thc inrlivirlual nrice are blocked by sex: lemales (8,) and males Br).
lnliriluult (l | . . . 1,,\
\\ lrt'rr llrr' r'llt't l ol t';rt'lr rlrlrtr' (or lrerrtttte nt) ol' lltc intlel-rcrtclcnt vitriablc is
rrl(',t\ltlt'tl rtll lltt' :;tttt(' lll(ll\l(lttttls ( tt'lt('(tl.'tl tttt'(t\lttt'.\ rl<'.:i,qtt'. tliSCttSsCtl llftCt' itl
tlrr', , lr,rIlt't ) llt,' rtr,ltr t,lrt,rl', ,rt,' ttttltt,tlr'tl lrl /, ,, lrr llrt' tt'1lr':ttr'tl ttt('itsut.cs
Blocks by sex of
individuals Individuals
Noon (A1)2
S,,,.
Midnight (A\2
Sr,-'
DESIGN OF RESEARCH
Table 6.5. A ltypothetical exuntple o/'a rt'peated meu.vure)^ experimentul cle.sign u,secl
to detarntine the e/fect o./'time o/-day on activity o.f'ltouse mic'e. Fotu'mule antl.firur
/bmole house mic'e n'cre rantlomly .selet'ted urul placed outtloors in t'uges vith running
wheels in order to measure the ntmtber o.f ntiruttes eac'h individual ntouse ,\pent using
tlrcir running wheel tlurirtg one hour ut ruton (1200 -1300) and one ltour at ntidnight
(24004100). The octivity data in tlte tuhle are.t'ront the.fir.st cluy's nteusurentents.
( See text ./br./urther e-rplanotion)
Time of day (,4)r
BASIC EXPERIMENTAL DESIGN
Measurernent(s) (x,,)
A measurement is the property (category or quantity) of the dependent variable
(behavior unit) assigned to an observation. In all experimental clesigns, except the
repeated measures design, each measurement is made on a different inclividual. [n
the repeated measures design illustrated in Table 6.5, the measurement of minutes
of wheel running is made on each individual (1) under each value (noon ancl rnid-
night) of the independent variable (time of day). When the elfect of only one
Independent Variable is being measured. the subscripts of ,r denote the sample (i)
and the number of the measurement (7), which is also the number of the individual
in a repeated measures design (Table 6.5).
Another example of the use of sonle of these terms is provided by Topoff an6
Zimmerli's ( 1993) manipulation experiment on the takeover of colonies of slave ant
species (Rtrntit'cr sp.) by queens of a parasitic ant species (Polyergus brevigeps).They
introduced each of ten Polvergu.r queens who had attacked a dead F. gnavuqueen
into five colonies each of F. gnuva and F.oc'c'ulutu. They determined whether
l\t1.1;gt'gv5 queens wor-rld be accepted by colonies of the same species as the dead
(lueen (F. gnuvrt) and colonies of another Forntic'a species (F. occulata) (Table 6.6).
. Independent variuhle: Slave ant species (Fornticusp.)
' Treotments:They introduced the parasitic queens into colonies o[ two
species: F. gnut,a and fl occ,ulota
' Santples: One sample lrom each treatment (f, gnrv, and F. ot,culuta).
Each sample consisted of measurements from five different colonies.. Depentlent yuriuble. Takeover of colony.
' Meusurement'. Two measurements of the dependent variable were made
for each of five colonies: category data: Takeover? (yes or No) euantity
data: Takeover time (min.)
6.5.2 F)xperimental designs
t )rrlv livc cxperimental designs will be discussed in this book. For a more extensive
'lrst'ttssioll ol' cxpcrintcntal clesigns applicable to animal behaviorresearch you
'lrottltl cotlsttlt orlc or tnore of'the texts devoted to that topic (e.g. Kirk, l96g;
l'ltr';trrls' lgti-5). l'irt'gootl cliscussions ol'time-series, single-case (single subject)
, l('\rln\. eorrsrrll K r.;rtoclrwill ( l97tt) irncl Kazdin ( l9g2).
I lrt'lrrt't'\lr1'1i111.'11trrl tlcsigrts tlisctrsscrl be Iow can be cliviciecl into two categories
tr t.ltlltl,' l() trltt'lltt't lllt' tt'st';trr'ltr'r rvrll bc slutlying lhc elll.cts tll'.ne or two inde-
l','tt(l('nl t rrI t,rlrlt's
Females (8,)
Males (8,)
Il
I)
I3
I4
I1
IZ
I3
I4
I I .3 (.r, ,)
8.6 (-r,r)
10.5
9.3
9.6
10.3
r0.9
9.1
52.2 (r.,)
49.4 (.r",.)
50.5
51.7
50.0
5t.1
52.6
s0.3
Notes:
I Independent variable.
2 Two values of the independent variable.
3 One sample of measurements from each Value of the Independent Variable.
design illustrated in Table 6.5, there are four female mice (1, ,) and four male
mice (1, o).
Dependent variable ( s ) (Y)
The dependent variable is the behavior unit on which nteusLtratn('nl,r urc nratlc. l'htrt
behavior unit will have one or more properties in which observations will dil'lcr irr
some measureable way (e.g. occurrence, fieqr.rency. duration. Iirtcncy). 'l'lrc rlcpctt-
dent variable in Table 6.5 is total tinie sperlt whccl rurrrrtirtg rlrtritrg caclt ortc-ltotn
sample period.
' One indePendent variable
Completely randomized design
Randomized block (repeated rneasures; matched pairs) design
Incomplete block design
Latin square
' Two indePendent variables
Completely randomized two-factor design
Almost all the more cpmplex designs, not discussed here, can be built by combin-
ing two or more completely randomized or randomized block designs (Kirk' l96tt)'
Statistical tests (Chapters 12-11) will be provided lor analysis o1'data fiom cotl-
pletely randomized, randomized block, repeated measllres. nlatchccl-pairs. ittttl
completely randomized two-factor designs.
Most of the examples provided for the experimental designs dcscribctl hclou'
are based on Vives'(1988) laboratory stucly of parental chtlicc by llrvill c()l)vit'l
cichlids (Cichlusonta nigrulfasciutunt). He released the lurvitl cichlitls itllo tlte t'e tllt't'
of al6.litre aquarium where they could choosc to stity itt closc 1'rt'oxitttitv lo itttlt
viclual ciclicls held in scrccnccl cnclosurcs:rl cithcr cnrl ol'lltr'rttltrttittltl (i t' trtlltttt
j cm 6l' cpcl6strrc c6ltirrtrrlsly lilr l5 nrirr.). 'llre llrrvlrl t'tt'ltrls \\'('l(' l;ttst'tl tttltlt'l
,ttc .l' lu,() (.()l)(liliorrs: L irr llrt' l)rr'\('n( (' ol prt'rlrrl()l\ ()l l11. ttt 
) llol ltt llrt' 1rlt"'
(.ll(.(. (rl lltt.tl;tlrlts trl ll \ S()||l(. trl lllt. (.\;lllll)l('.. lrltr\ ltl...l .rtt. :lt llt.rl 
..r1)(.1 llll(.1|1..
BASIC EXPERIMENTAL DESIGN
that Vives conducted; however, most of the data, and some of the experiments, are
hypothetical.
6.5.2a Completell' randonized design
This is one of the simplest designs, but it can be used to compare any nurnber of
samples (or treatments) of a single independent variable. The samples are the
qualitative or quantitative diflerences in the independent variable which you have
hypothesized have a measlrrable effect on the behavior you are studying. [f the
experiment is ntensurutive, the measurements taken in each sample are from indi-
vidr-rals rartdomly selected lrom tlte population; the experiment may consist of a
single sample. If the samples are treatments in a ntanipulation experiment, there
must be a minimum of two treatments (or treatment plus control), and individual
animals are randomly assigned to each treatment. A t'ontolis often considered a
'zero' treatment in which everything is the same except that the experimental
variable has not been imposed. However, a control can also be: l. a'procedural'
treatment (e.g. mice injectecl only with saline versus saline plus drug treatment);
or 2. any treatment against which other treatments are compared (Hurlbert,
l 984).
One suntplc
Tabulur.fbrnt One sample (or treatrnent) of tlie independent variable
S,,
rtt
-r t:
,rt:
.ri,,
Sirmple Mean:i,
\ ,, : tlie onc sunrplc (or one treatment) of the independent variable
r,.-Mcasurcnrer)t ol'the dependent variable on the second individual in the
sitrnplc.
ir rr birr'()vcr ir total inrlicutes the mean lor that total. The dot in the subscript
tlcnoles lltc vrrrirrblc ovcr-which the surnmation occurred; in this case. this is
tlrt'nrr'rrrr lirr llre srrrrr ol'thc ulcasLrrenrcnts in this one sample.
lt,rrttltl,' \/rr('\(l')ss)l)llt ,r l);u('nlr'rt'lrlitl inclrt'lrol'lhcscrccnctl cnclostrresatthe
('n(l\ (rl llrr'.rrprilnunl rrrrtl rlr'lt'nnnr('(l rrlrt'llri't tlrt'ir l;tttltt't'llosc lo stity itt l-ltoxirn-
tl\ lo rltt('ot lltr',,llt,'t ,,1 llt,'l),ltt'ttl',, ot t lt,'',r'ttr'tlltt't
l3r
130 DESIGN OF RESEARCH
Table 6.6. Polyergus queen tukeot'er o/'unreluterl F. gnava c'olonie'; uncl o./'
F. occulata colonies
Foreign F. gnava colonY F. ot'culata colony
Colony
Successful
takeover?
Takeover time
(min.)
Successful
takeover'?
Takeover titne
(min.)
+
+
I
2
-1
4
5
+
+
+
+
+
l5
70
I
60
20
NA
NA
2 days
NA
3 days
Notes:
NA: Not applicable. t : Successlul
Source; From ToPoff & Zimmerli
takeover; -: utlsuccessful takeover.
( 1993). Copyrighted by Academic Press.
ti
I32 DESICN OT.RESEARCH
S,rr (One parent at each end of the aquarium)
+ (r,,; the first individual in the sample is indicated a having chosen a
parent)
(-r,,; the second individual in the sample is indicated as having not
chosen a Parent)
:
+ (-r,ur; rhe 69th individual in the sarnple is indicated as having chosen
a parent)
Of the 69 individuals tested.47 chose to stay in proximity to one of their parents,
and22 did not choose either parent.
Ttro sttntple,v
Tabulcrr Fornr
Sample means:
S,,,
.Y: 
t
,Y:z
l-1
:
:-
.Y:.
Grand mean:.r
where: S,,:Sample 2 (or Trealment 2) of, the independent variable
.y,.:MeAsurement of the depenclent variable on the second individual in
samPle 2.
,yr:a bar over a total indicates the mean for that total. The dot in the sub-
script denotes the variable over which the summation occurred; in this
case, this is the mean for the sum of the measurements in Sample 2.
E.turnple Vives ( 19S8 ) found that the length of time until a choice was ntatclc ( rcttc-
tion time:latency to choice) tended to be shorter for young lrom brtltlcls rcirrccl itt
the presence of predators of yollng versus those raised with no pretlittors ol' yottttg
present (see Table 6.7).
Therewere33inclividualsinSample Alan<1 l4individrtitlsitrsrttnplc.ll.'l'lrc
rJata show that the first individual(-r,,) trom a broocl ritisetl 'uvilh 1-rt'ctllrlot's (SrttttPlc
S.,,) took 123 s to make a choice. Thc last intlivitluirl (t,,,) ll'ottt:t bt'ootl rrtist'tl
wilhttut precl;rtors prcscnt (Santplc ,S ,.) lotlk 156 s. to tttltke tt ,-'ltoit't'. '
BASIC EXPER IM ENTAL DESIGN
Table 6.1. An exumple o/'dutu in a c'ontpletel'; rantlotni:etl clesign tt,ith ttro sumples
(see tert frtr e.rplunution)
l3l
Groups from broods raised
with predators
S,,,
Groups
without
S,,
from broods raised
predators
123 (.r, ,)
207 (.r,,)
186 (.r,.,)
:
42 1 (,r, ,,)
305 (,r,,)
215 (,r.,,)
3l I (-r,.,)
:
356 (.r,,*)
S,,
-rtt
.Y t:
_r t:
l"
-Yl.
Sourt'e: Based on Vives (1988).
Three or nlore sumple.s
Tubulur.fbrnt
S,' sr, "' s
Y:r
Y::
Y:r
-r "Y" ... -r
Sample nreans:-r, .Y, i.,. ... .\,
Grand mearn:,r
.S.,, : Sample I (or Treatment I ) of the independent variable
-rr,: MeAsurement of the depender-rt variable on the second individual in Sample I .
.I'r :a bar over a total indicates the mean lor that total. The clot in the subscript
dentltes the variable over which the summation occurred; in this case, this is the
mean ftrr the surn ol the measurements in Sample l.
liturtrplt A thirtl sumple coulcl be addecl to the example above by addilg a
sitttlplc ol' yotttlg rltiscil in the presence of predators of adult cichlids. Reaction
titttcs wotlltl tltcrt hc titkcrt ll'om rernclomly selected individuals from eachgroup
(scc lrrlrle (r.X).
Itt lltts ltl'Potllt'lrt'rrl erlttttplc rvc lutvc trscrl 2l ipcliviclguls 1[rm brgods raisecl i.
lllr' pt('\('n( (' ol p11'11;1[1ls ol ;rtlrrlt gigltlirls (S;rrrrltlc A1;. 'f[c lirst i,rliviclt*rl tlc,_
rtttt'tl lr llrt.,,,tlltl) ( r ,, ) lr:trl:r tt';tr.li,rtt ltttrt.ol l.) I s(,(.()lt(ls.
T.
Y.
:
t34 DESIGN OF RESEARCH
Table 6.8. An exumplc rf'a c'otnpletely rurulomized de,sign v'ith three suntples
illustratecl with hl,pothetit'al data./rom lurval t'ic'hlids (see text.fir explturution)
BASIC EXPER IMENTAL DESIGN
6.s.2b Randomized hrock, repeated meesures and matched pairs designs
Ra ndom i: e d ht o c.k d e.t ig rt
This design controls lor additional variability (expressecl in the error effect) byassigning subjects that are similar in one or more characteristics (e.g. same sex, age,litter; to blocks' That is, subjects within each block should be more homogeneousthan subjects between blocks. Blocks can also be treatecl as a second independent
variable (e'g. two-way analysis of variance, not discussed in this book).
Tuhulurjbrm
Siintples of indepentlent variable I
Block
S, Sr, Sr,... s, means
'Ytt -Y:r -Y3r .'. -\,r -r l
rt
Grand mean:i
. -Each 
-r,, is a measurement from a difrerent individual or a total fbr several indi-viduals in that brock and sample. hidividuars are brockecr (e.g.B,) according tosome characteristic such as sex. age, genotype, place, or time.
Example vives (1988) tested the larval cichlids at a. age of two days free-swim-ming, because by that time they f'eed exogenousry and show good mobirity, and theyhad previously been shown to responcl n-rost readily to models when less than sixdays free-swirnnling' If it were not possible to lrave large numbers of young availableat tlie age tll'two days f ree-swimming, an<l it was f'elt that age might have an ef1-ect ontheir choices' then a ranclomized block design could be used. From the individuals
raised witli precltrtors of young. five would be ranclomry selected and testecl at age Idtty' itttothcr livc at age ?, etc. The same procedure would be used lor the individuals
raiscd wiIhouI ;-rr-cdutors of young.
-I'lrc 
ltyPothclicrrlrlittit in Tublc 6.9 show that the total time to make a choice for(lrc lir,e itrtlrvitlrr;rls r.rrisctl wirh ltrcclirtors ol -young, ancl testecl at age I clay free_srt ittttttittr' ( t ,,) ttlts (t'50 se..ttrls. 'l'lrc f irc irrtlivitluirl linres nraking ,p that tot.l\\'oltlrl lrr. tlt'st1,n;tlt,rl lrs r, 
r r. \ rr,. \ I I,. \ r r r. ilnrl r,,,.
135
Raised with
predators of young
S,,
Raised without
predators of young
s.,,
Raised with
predators of adults
sr,
123 ("r,,)
207 (x,r)
186 ("r,,)
421 (-r,,.,)
305 (-r,,)
215 (.r.,.,,)
3l I (.r,.,)
356 ("v.,,*)
216 (.v,,)
215 (.r.,)
195 (.r,,)
323 (.r.,,,)
Linettr ntodel A simple equation can be used to show all the sources of variation
that affect the indiviclual measurements in the three completely randomized block
designs described above.
.r,,: lt,* o,* ,,j
The rnodel (equation) states that each individual measurement (.v,,) is equal to
the population mean (p) plus the sample (or treatment) elfect (a,) plus an error
effect (e,r) which is unique for each individual subject.
As in most experiments, population paretmeters are not known. but the samples
are used toestimate those parameters. In theexamples of experiments above,lt. ai
and e,, are unknown: but they are estimated by the following:
&:,t (estimates p)
ir,:(.r-', -.\- )(estimates rr,)
e,,:(x,,- I ,) (estirnates e,r)
The error elfect is the summed elfect of all the uncontrolled rnrisurtt't, turiultl<,.s.
that is. all of the elfects not attributable to a particular sarmple (or trcatnrent). Wc
can rearrange the linear model to show that the error el-fect (e,,) is whll r'crnrrins ol'
ari individual measurement (.r,,) alter the sample (or treatnrent)cll'cct atrrl 1'lo1'rulir-
tion mean are substracted from it.
Blocks
Bl
B,
8,,
Sample
means:
-r.l
r
I
rl
I
ri
I
I
',1
?,r:'v,r-(&,*P)
136 DESIGN OF RESE,ARCH
Table 6.9. A runclomi:ecl block design illustruted with ltypctthetit'ul duta.fbr tha tinrc
it took larval cic'hlitls o/ dif/brent ages to c'hoose to stu1, near one d'their parents
BASIC EXPERIMENTAL DESIGN
Table 6.10. An e.runtple of'u repeutatl nteu,sure,s
with hypothetical cluta.front larval t'ichlicls (.see
r37
des'ign n'itlt twu ,santple,s illustratetl
te-rt fbr explanation)
Age
(days free-swimming)
Raised with
predators of young
S.,,
Raised without
predators of young
S,,,
Individuals of age two days
flree-swimming raised with
predators of young
No Odor of predator
So,
Odor of predator
Sn,
I
2
1
J
4
Re pe u t e d nrc us ure s des i gn
The repeuted measures cle,sign is the same as the randonizetl block design except that:
r Individuals (e.g. 1,) are the biocks (Table 8.4)or subsets of blocks (Table
6.s)
u A measurement in each sample (or treatment) is made on each individual.
For example. the measlrrements,yrr,-r:r . . . ,r,rr are all rnade on individual
I t.
Tuhulur fbrnt
choice when no predettor odor was present,and it took 175 s. when the odor was
present.
650 (-r,,)
587 (,r,,)
673 (-r,.,)
706 (,r,,,)
1235 (-r,,)
1307 (-rrr)
1214 (xr,)
1292 (x.^)
Il
I2
'I,u
203 (-r, ,)
185 (r,,)
226 (.r,,,,)
175 (.r.,)
168 (r,,)
213 (.r,,,,)
fu[ u t clte d pu i r.s cl e.t i gn
This design is a subset of the randomized block
Either design is usually relerred to as mcttchecl puirs
ments)are used.
'fubulur 
fitrntut
and repeated measures designs.
when only two samples (or treat-
.Y, .tr ... .t,
Grand mean:-t
E.rumple If we decided that the greatest ell.ect ol being ruiscrl r,vith pretllttot's ol
young was shown by young at age 2 days free-swinrtling. wc ntigltt Iltctt cltoosc lo
use ten individuals from that age groLlp to test lirr thc clll'ct ol'1'rt'ctlrttor rttlrtl itt tlrr'
test aquariLlnt on their time to nrakc it chrlicc. Wc rvottltl I'ltntlotnlv sr'lr'r'l lirt'itttlt
viduals to be testccl in (hc pl'cscncc rll'tltc otlor lit'sl. tlte otlrr'r'lir('\\('\\'oltltl lt'sl lttrl
turtlcr 1lrc crltttlilirltts ttl' tto 1'rt'ctlltlot otlttl
l lrt'lrrlltrlltr'lrt';rl rl;rl;r rrr l;rlrlr'(r lO rlrorr', llr;tl ltl(lt\ t(lrlrl /, lool' t0 l', lr, ttt,tl\(',t
Samples of independent variable
Blocks or
individuals S.r, S.r,
'Ytt -Y:l
-Yt: .r::
!:1
Srrntple ntcllns: .\=,
Grand mean:
l"'\(tt)tl)l( Sirlcc both ol'the extp-rples lor the randomized block design and the
r('l)crllc(l lllcilstrl'cs tlcsign (above) have only two samples, they are also considered
t t r;rlt'lretl plr r rs tlcsigrrs.
I tttt',tt tnrtrl<'l
Iltt' t'r;ttltlt.11 lot 11,..' tlttttl,rttttzt'rl lrlot'k. lr'l)t'lrlr'rl ltrclrsrn'cs lrntl ntirlcltctl pitirs
,1,",t1'1s', ul( lu(l(.,. /i tlrr't.llr.t I trlIr rl,ul;rlrlt.lrr Ilrt.Tllr lrlrrr.[ (or nttlrr itltlrl):
Samples
Individuals
Il
I2
;
Sample means:
of independent variable
sr S.r, sr., "' s.r,
-Y: r -Y-r t
-Y:: -r::
-rr,, -rr,,
_\'
-\- .n:
,Y
Bl
B.
B
tr
,r
.tr
138 DESIGN OF RESEARCH
-Y,,: P*u * F,*r,,
Therefore, by assigning similar subjects to blocks (or taking a measurement lrom
the same individual in each sample) we have partitioned an additional source of
variability out of the error effect. We can show this by rearranging the litrear model:
i,,: x,,- (&,+ F,+ tt)
Estimates lor g, and rr, remain r and (i, --\' ), respectively.
F,:tB ,- t ) (estimatet B/
therelore, the error effect is estimated by:
€r:r,r-[(.r,-x )+(r- -t )+-t ]
If the block effect (F,) Ir appreciable then we will have beeu successful in reducing
the error eflect (e,,) by blocking. The relative power of the statistical analysis we use
will be increased by reducing the error effect as much as possible.
6.5.2c Incomplete block design
This design is applicable when the number of subjects available lor study is not
large enough to measure each sample (or treatment) effect lor each block; that is,
you cannot complete a normal randomized block design.
Tahulur /itrm
Samples of independentvariable
Block
s,r, s.r, sr, meansBlocks
Bt
B2
B1
Jrr
-Y::
J 
t .., 'Y::
\lt
r-r2
J.r
t,
-Y.
Sarnple means: .[', tr. j'r
Grand mean:.t
This design is balanced. which means that each block contuins thc sittnc ttuttthct.
of subjects. each sample (or treatment) occurs thc satnc rrutnbct'ol'titttcs. lttitl sttb-
jects are assigned to the samples (or trcatt-r-rcrtts)so tlutt cltclt possiblc;t;til ol lte;tl
nrent lcvcls occurs within circlr block lur c(ltutl nrttttbcr ol titttr's. Itt p;trtrlrlll
hltlittlcctl tlcsip,tts s()lllt'l)llils ol'ltt';tllttt'ttl lt'rt'l: t't't'tll ltrl'1'1ltt'l ntlltttt lltt'lllt't'ks
nl(rt(' (rllt'tt Ilt;ttt rl.I ()Iltt't 1r;tttI
BASIC EXPERIMENTAL DESIGN
Table 6.11. The densities o/'mare untr/bnrare wrocrruts u.yecr in Kinsey's (r976)
sttrdy of ,social behu'r,ior in AIleghetry wtxtclrat.s
Sexes in groups Density (individuals per 65 m2)
139
Xx
6
X
X
X
x
2
x
X
X
912 t4
All Male
AII Female
Mixed
As an example, Kinsey (1976:181) tested his research liypothesis that..
Allegheny wooclrats (Neotomo.floriclurut mttgi.ster) would exhibit territorial behav-
ior when confined in relatively low-density populations in a large observation cage
and at populations of higher density would e.xhibit increased agonistic interactions
and a dominance hierarcliy type of social organization'. He placed wilct-trapperJ
male and female woodrats together in a 65 mr enclosure at densities varying from 2to l4' Howevet in this partially balanced design not all densities (treatments) were
represented nor did each group (block) contain both males and females. For analy-
sis, the cJensities were combi,ed into two groups: low density (24) and high
density (5-14). Table 6.ll shows the densities ancl sexes that were represented in
the groups used.
At this point the qtrestion arises: If I have a limitecl number of subjects should I
go to an incornplete block design or lall back on the cornpletely randomizecl clesign,?
Ytu .should ulvul'.t ,;rrit'e ro trcsigrt rha dcttu coilection irt .tut,rt a trut)) u.s trt reduce rrrc
crntr ef/bct as ntuch us possihle.
Lineur tnodel
The equation lbr the incomplete block clesign is the same as that fbr the randomized
block clesign:
.t',r:it-t,* tt,1- p, I e
d.\.)/ l,utin .\qttilrc tlcsign .
I lrrs tlcstgtt ttscs hlockillll t() I'c(lLlcc the error ef fbct from two nuisance variables. The
It'tt'ls,l'lltt'luortttis;tttce tltt'iltblcslrrclrssigrrcdtotherowsandcolunrnsof aLatin'-(lll;llt' \irtt tttttsl lt;tVt'lltr.'s;ttttr'nttnrber ol's:unplcs rll'circh pf the three variables
(lltr'rrrrl('l)(.lt(l(.nl rlrrlrlrlt.rvlr,,st.t.l]t.t.l \.()u ilrt.strrrlVirtt,ltttrl tltc lwtl ttttisiutcc vitri-
,rltlt'ttlt,t',,','1lt't 1., \ilU;il(. 1);il ltltilt11J,,,, 1rUl 11t llrt, lrl.1t.hs)
t40 DESIGN OF RESEARCH
Tabulu".fbrnt
The exanrple below uses three samples of the independent variable of interest 
('4)
and three samples of each of the two nuisance variables (8.O. The C 
variable
samples are assigned to each of the cells in the Latin square in a balanced 
fashionl
that is. each level of the c variable is equally represented in both the rows and
columns. This necessitates the Latin square having the same 
number of rows'
columns. ancl levels lor each variable'
Independent variable I
Nuisance
variable B A 
1
A, A1
Bl cl
"rttt
cr
'Yt tt
(-, C] Cl
'r t 2: 'rl:-, -Yl: t
cr cr c,
.r 1..,-, -Y:r t 'Y3-,:
The subscripts tbr each measurement (-r,,^) denote the level of each inclependent
variableintheorder A,B.C.Forexample,.t,,, denoteslevel 2lorvariablel'level 
3
lor B. ancl level I for C. Each measurement ('r,,^) is taken on a different 
individual'
The individuals are randotlly assigned to the combinations of variables'
E.rumPlc
Using our example of the experiment of choice by larval cichlids we 
could Irleasure
the effect of three different regimes of raising the young on their time 
to make a
choice, while at the same time blocking for color morph and 
age when tested' The
fbllowirrg variables can be applied to the tabr-rlar format ttbove:
Inclependent variable I (raising regime):
,4 
': 
raised without the presence ol predators
lr:raisecl in the presence of predators of young
1.,: raised in the presence of preclators of adults
Nuisance variable B (color morPh):
B,:gold
.Br: green
B-,:wilcl tYPe
N uisance varitrhlc ('(lgc wllctt lcstctl ):
('t I tlltr ltt't'-:tritttttlittl'
(' .)tllt\s ll('(' \\\'lllllllllll'
( I,l,rt"IIr'r''\\lllllllllll'
BASIC EXPERIM ENTAL DESIGN
Lineur ntodel
The equation for this design inclr-rdes the zl variable effect (a,). the B variable ef lect
(F,). and the C'variable eff-ect ( r'^).
.rilr:F* u,-t 9,* I'l t€,lr
By partitioning out the two nuisarnce variables, we have reduced the error ellect.
This carn make the Latin square a more powerf ul design than either the completely
randomized or randomized block designs, although it is rarelv used in ethological
research.
e,,r- :,l,rr, - ( a + B +ir, + 0)
The lollowing matrices show the assignr"nent of levels (1,2.3, etc.) of nuisance
variable C to the cells of a4x4x4 ancl a 6x6x6 Latin square clesign.
A
3,1 B
B,
1x4x4
Variable
B l2
6X6X6
Variable I
123456 I
123456
231-561
3 4 s 612
4 5 6 | 2 3
561234
612 3 4 5
l 1234 l
2 2 3 4 | 2
3 3 4t2 3
4 4t23 4
5
6
B.
6.5.2a Completell' ranlomized two-factor design
This design is usecl to measure the effects of two independent variables. It can be
extended to three or more v'ariables by continued blocking of the variables so that
blocks are split into addititlnal bkrcks of another vzrriable. Each measurement (.v,,)is
taken on it clill'ercnt incli','idr"ral. The indivit'luals are randomly assigned to the com-
binatiorts ol' vu riablcs.
( )rtc ,strntplt
Thltrrlur f ot ut Onc santple each of indepenclent variables I ancl B
^\ ,,
\.,1
:
^\,,,
\l,t
'1'
i
I
DESIGN OF RESEARCH
Table 6.12. Exttntple o.f u t'ompleteb' rundomized two-
fitt'tor design v,ith rtne suntple.fbr euch vuriahle
illustrtecl with hypotheticul tlata./br lorval c'ic:hlids (see
t t'.t t .f i t r t'.t' P I u t tu t i t t n )
Raised in presence of:
Predator Visual stimuli
S,,
BASIC EXPERIMENTAL DESIGN
Table 6.13. Example of a completely randomized two-factor design with two
samples illustrated with hypothetical data for whether larval cichlids of two color
morphs and raised under two conditions chose to stay in close proximity to one
of their parents
Independent variable I
Predator odor
sil
Color morph
Totals
Raised with
(N:40)
S,,
predators Raised without predators
(N:40)
S,,
2l 3 (-r,,,)
162 (-r,,r)
235 (-r,,,,,)
187 (.r,,,)
219 (-v,,,)
:
174 ("rr,,,)
Gold S,
(N:40)
Wild type Su,
(N:40)
Totals
l6 (,r,,)
l7 (.r,,)
JJ
4 (.Y.r)
l0 (xrr)
t1
20
2l
47
Example In the study of choice by larvalcichlids, we might want to test 
the effect of
being raised in the presence of the odor of a predator versus being raised 
where the
pre<lator can only be seen on the reaction time of the cichlids (time to mztke 
a choice)'
We would rundomly select inclividuals to be raised under these two conditions 
and then
randomly select 10 individuals from each group at age two days free-swimming 
tbr
testing. They woulcl be testecl with neither predator oclor nor visual stimuli 
present'
In this hypothetical example (Table 6.12). the second individual from 
the groLlp
raised in the presence of predator odor (-r,,,) took 162 seconds to choose 
one of the
parents.
Tn' o s arnp I c,s o.f 
' 
ttt' o i n tl a p e ntle n t w r i u b I e s
Tcthulur lbrm
Samples of indePendent variable I
Samples of
independent
variable B
S,,
S,,
Variable I
means: \ , .\'. \''l
( it':tlttl lll(':111. i
being raisecJ with predators of young on whetlier age two day free-swimrning larval
cichlids choose to stay in close proximity of a parent, or not.
In this hypothetical example (Table 6.13), 47 of the 80 cichlids tested chose to
stay in close proximity of one of the parents; 33 of those were raised in the presencre
of predators, and27 were ol the wild type. Seventeen had both features; that is, wild
type raised in the presence of predators.
Thrac, or tnor(, ,suntples o.f' two intlelterrclent variublcs
Tubular fbrnt
Samples of independent variable I
Samples of
inclependent
variable B
,t,,
,sr-,
,\',,,
,\,,,,
Vrrrilrlrlt' .l
S,,, Sr, "' Sr,,
I
Variable B
means
s,,
Variable B
means
S,, s.r,
'Yr t 'r:t
rt: J::
Y.r
.r.2
:
r
-\- 
|
,tl
rn ,r:t .Y-rt
\ r: 'Yj. 'Y::
Iri -Y:: 'Yr
t,,, t,,, 
',,,
1,.'t,ttttltlr, lrr tlrr. (,\l)('t nn('lll u tllt ( ll()l( (' Itr l:rt t ltl t tt ltlrtl''
ll,,lill' :t.,,tlt ('\,tttrIlr' tt,'.1.'. l.lr' lil l.lt,l' 'tl lltt t t'tltlrtttt'tl t'llt'r
rtlttr lt \\(' ll;l\(' lx'('ll
| ill r r)lilt tll(,t;,11 ,1;1,1
145
Color Morph
Raised with
predators of
larvae
( 1/:60)
sfl
Raised without
predators
( 1/:60)
S,,
Raised with
predators of
adults
(N:60)
s.r,
DE,SIGN OF'RESEARCH
Table 6.14. Exuntple q/'u t'onrpletell' runclonti:ctl twt-firt'tor tlasign vith tltree
strntples illustrutacl y,ith h!,potheticul clutu.lbr v'hether lurvul cichlicls of'three c'olor
morph,s ttncl raisetl uncler thrae t'onditions cho,se to sttt.v in t'lo,se prorimity trt one o.f'
lheir purents
Independent variable I
BASIC EXPERIMENTAL DESIGN
baboons and found that the researchers tended to select the largest group available
to them as their study group; they point out that this will likely introduce significant
biases in analyses whenever group size is an important independent variable.
When selecting individuals for a randomized design or selecting random samples
of behavior from an individual, it is important to understand the dillerence between
r a n do nt, lru p h u : u rd and o p p o r t u n i s t i t' samples.
' Runclont suntp[e'. An individual selected from a population, or a measure-
ment taken from an individual, in such a way that all possible samples
have the same probability of being selected. For example, all individuals
in a population could be assigned numbers and then the sample of indi-
viduals to be observed could be randomly drawn from a hat.
' Hupha:urd suntple: A sample taken on some arbitrary basis, generally con-
venience. For example, we might take measurements on the individuals in a
group that are closest to us, or we might take measurements belore lunch
and after dinner, or when we think the animals are likely to be most active.
' Opportuni.vtit'suntple'. A sample of behavior taken when it occurs in any
individual in the population being observed. The individualselected,
then. is based on the behavior whish it is performing. For example, we
might be studying an unusual behavior in a species that forms large
leeding aggregations; we watch all the individuals untilwe see the behav-
ior occur, then we record our observations on that individual perfbrming
that behavior (all-animalall occlrrrences sampling, Chapter 8).
Some researchers use the term rundorl to reler to the way in which their samples
wcre collected. when really what they collected were huplta:urd samples; for
cxample:
This study is based on facts gleaned for the most part from random
observations. [Loran;, 1935;90J
In son.rc cirses, research by early ethologists sullered from a lack of knowledge
;rl'rout cxpcrinrcntal clesigns. For example. Tinbergen admitted that in his earlier
strrtlics with grayling butterflies. they had presented their models in a haphazard
r :rlltcr tlrlrrt t'irttrlr)nr scclLlcnce.
Wc v:rrierl thc sccluence ol the models irregularly (not being
soplristicirlcrl cnough to vary them in a random way).
ITinbargan, I958:I82J
,\lllr,rrrl,lr lrrrt'riu)(l()ln srrrrtplinu is ol'lt'rt tlillicrrlt in ctlrologicul lield stuclies. it is
.ur ,r',',unrPlrr)lr ()l nr(rrl sl;rltrltt';tl lt'sls 'llrt'rt'li)r('. t('s(':rtt'ltet's sltottltl ctltttbitl thc
l('iltIl,tlt(1il l,'l,rl't'llt('(',t',\ \\,t\ rrrrl ,ilr(l ',,rtrrIlt'lt;rIlt;tz;tttllf . tltt'f sltottltl tttltke
Gold S,
(r/:60)
Wild type S,
(l/:60)
Green So,
( I/:60)
l6 (.t,,)
l7 (.r,,)
I 3 (,r,,)
4 (,r,,)
l0 (,r,,)
7 (-r,,)
l2 (,r,,)
l4 (,r.,)
l0 (,r,.)
I
Exuntplc As an example of this design we will add to the example given above (see
Table 6.14).We will add an adclitional color morph (green) and atn additional condi-
tion under which the young are raised (with predators of adults).
Linettr ntsdcl With the completely randomized design with two indeperrdent vari-
ables we have includecl the effect of independent variable A (4,), independent vari-
able B (F,) and their interaction (7 ).
t,,:F*u+B+l,ilr,i
6.5.3 Random, haphazard and opportunistic samples
In the experimental clesigns clescribecl above. it is assumecl thirt irttlivitlttirls (ol'
groups) selecte<J to receive treatments, or selected tbr observittiott lrtttl bcltrtviot'rtl
measurements, are ranclomly selected from the poptrlation. Irl lltct. it is ttsrtrtllv Vcl'v
difficult(ifnotimpossible)toaccomplishthiswlrcrlctltttlttctitlgcllttlltlqic:tlt...s..lttt'lt
in the field. Instead. we atternpt to suntplc a lul'gc ntrrnbcr ol'intlir,itlttltls ttttrl st'lt't l
indivicltrals in a wity tllitt wc llclicvc t'csttlts ill:l ,r'rr'rt,,11111t11'111t1t1tt\ittrttlrrtrr ttl il
t.itttrltltt.t sitptltlc.'l'ltc resclrt'r'lte t rnrrst lrltr'ntpt ltl rtvotrl ;t lltltst'tl r:ttltPlt' ll()lll ;l l)()l)tl
llttitltl. l'ol t'r;ttttPlt" '\'ltltt tttltll illl(l I )ttttlrlrl ( lt)fi 
)) t'\;lttltttt'tl 'l ltt'ltl .,ltttltt"' 'rl
146 DESIGN OF RESEARCH
every attempt to achieve or approximate random sampling. S. Altmann(1965a:494)
'. . . tried to sample at ranclom from among the monkeys. However, no systematic
randomizing technique was used'.
Ethologists often sample opportunisticulb'from a large nnn'rber of animals that
cannot be recognizetl individually, especially if their interest is in a particular behav-
ior, or sequence of behaviors. For example, Cresswell (1993) studied escape
responses by redshanks (Tringa totanu,s) in response to avitrn predators by making
opportunistic observations of attacks by sparrowhawks, peregrines and merlins on
individuals in a large population of redshanks.
Opportunistic sarnples are neither random, nor completely haphazard' We
should randomly sample individuals, but instead we sample based on behavior, and
we do not know how many dilferent individuals are included in the sample. We can
only hope that with a large enough sample ol occurrences of the behavior we will
also have sarnpled a reasonably large number of individuals. Even if we could recog-
nize individuals and randomly select a sample of individuals for observatit-rn, the
chances of observing the behavior of interest would be remote without spending an
inelficiently long period of time making observations. For example, in Creswell's
(1993) study of recishanks. he observed 696 raptor attacks on a population of
200-500 ildividual redshanks. during 2551 h of observation. [f Cresswell haci ran-
domly selected an individual for observation from a popr-rlation of 200 redshanks,
that reclshank woulcl have had a probability of approximately 0.0014 of being
attacked during a one-hour observation period, if the attacks were randomly dis-
tributed throughout the redshank population.
A respectable attempt at random sampling diflerent individuals can sometitrtes
be nrade by stratifying your sample by sex or body size and attempting to sample
ranclomly within those groups. If you are observing a large group of individuals'
such as geese feeding in a field, you can divide the group spatially using an imagi-
nary grid or marker stakes placed in the field before the geese arrive. You can then
sample from different and distant portions of the grid assuming that an individLral
goose is unlikely to move that distance during your samplipg period.
When individuals can be recognized, it may still be dilficult to follow a ratldottt
sampling protocol because of the availability or observabilty of specilic inclivitltrlrls.
To make efficient use of your time, you might thenattem pt tt't ctluuli:t' thc rtttttrllct.
and ten"rporal clistributiol of observations among individuals. Firr cxlttlll.rlc. yott
might obtain l0 one-hour samples of t-eeding behavior lhrnr citclt intlivitlrral tlttt'rltg
each of three sample periods (early morning, noon. lltc ul'tct'noott) ovct' llte Pctiotl
of a month;however, this type of sampling protocol is ol'lcrr tlillicrrlt lo rtt't'otrtPlislt.
I :rttcrrrltlctl tp tlislrilttrle olrst'rr';tliolts t'r't'ttlv tlttottt'llottl lltt'rllrl'lr1'lrl
lt()uts srl llt;tl lirt r'ltt'lt llirtl ,lttl tttl't';tt lt ;ll'(' l)('l l()(l lot.t1'ttt1'
RELATIVE EFFICIENCY OF EXPERIMENTAL DESIGNS
behaviour was sampled during the morning, midday, and evening. This
was not always possible. I Yoerg, 1 994. 579 J
For a particular sample period, if you could not collect data on the randomly
selectecl individual, you should select another and continue that process until equal
samples had been collected lor each individual. Collins (1984) used instantaneous
samples on every baboon in order to estin-rate the amount of time each animal spent
in each part of the troop. However, he had difficulty randomly selecting the local
animal, so he settled on the following procedure which combined opportunistic
sampling ar-rd equalizing samples:
Sample subjects [focal animals] were selected in sequence from a
predetermined random-order list, but some choice had to be introduced
to speed up sarnpling. To do this. the list was divided into triplets, and
the subject chosen was the first one seen of the next triplet provided that
it 1a) was more than 25 m from the site of the previous sample. and (b)
had not been sampled during the previous hour nor more than once that
day. Some animals were however given priority over others in their
triplet (before the start of the day's sampling) il their sample total to
date had lagged behind . . ICollins, 1984:5391
6,6 RELATIVE EFFICIENCY OF' EXPERIMENTAL DESIGNS
A measure of the efficiency of an experimentaldesign should include the cost (time
and money) of collecting the data balancecl against the accuracy and validity of
those c1ata. The relative efficiency of two designs is often assessed by cornparing
thcir respective experimental errors (error effects). Experirnental error is the extra-
rlcous variation in the measurements due to all the nuisance variables. Its ultimate
cll'ect is to mask the ellect due to the independent variable(s).
Federer ( 1955: I 3) proposed the lollowing lormula to meersure efficiency:
/"'',\ f!.rr\
\-= / \ar',+:/
cllicicncy:-
(-) t++)
rr lrt'r'r' l rtrrtnbcr rll'srrl-l.iccts
r t'ost ol'tllrtlr collcctiott pcr sub-iect
rll ('\l)('nln('ntrrl e r rrrt'tlcgrccs ol'll'cctlotn
l ()r ( orttlrlt'lr'lt rttttlontizr'rl rlt'si1'tt:
r'ttot tll lol,rl.ll r.rtttPlt"-,ll
I48 DESIGN OF RESEARCH
where: totaldf:n- I
samples df: ntunber of sart"rples- I
ri:estimate ol' experimental error pef observation Tl]e experimental error
can be estimatecl by calculating the rnean of the deviations of each mea-
sLtrement frorll its samPle Inean:
f :rr,, - ., )'lI tt t. 1
I tt I
The subscripts clesigpate the two experimental designs. If the ratio is greater thau
one. then the lirst design is more efficient than the secolid. Because ol the liniited
controlethologists generally have i1field stuclies. compromises are usually necessary'
6.] DETERMINATION OF SAMPLE, SIZE
The suntplt,si:c is the number of nreasurements in a sample' Since in most experi-
prental clesigls each nrezrsurement is made on a diflerent inclividual. sample size
generally ref-ers to the nul. ber of individuals (sLrbjects) in the sample' Experimental
psychology and psychophysical stuclies are sometimes based on single-subject
(time-series) clesigns (Kazclin, 1982; Kratochwill. 1978)in which a very few subjects
are exposed to a series of treatments over an extended period of tiltle. ln coutrast.
most studies in ethology require the use of several subjects.
San"rple size needs ttl be aclequate to provide sufficient power lor ytlur statistical
test (Chapter ll), br.rt it shor.rlcl not be excessive. In orcler to determilie the sample
size required for your particular study. yor-r shor-rld have an estimate of the variabil-
ity of the data. This ca1be cletermined by gathering some preliminary data' or using
clata gathered during recclnnaissance observatious or by other researchers. and then
calculating the stanclarcl deviation of the measurements (see sectitln I l '7'6)' The
following lbrmula lor cletermining required sample size lSnedecor' 1946) tbr a test
of two means can then be used.
1:tabular'l'value (Table A5) at the selectecl ctlrlliclcrtcc lcvcl (sccti11ll I l'5)'
ancl lor the degrees of frceclom 1p. t)t)) itr yottr sillllplc
r/: tla rgin ol errtlr ( tnea tt X dcsi gtrtrtctl ltcctt l'itc,v )
sitv \\,C lvlrrrt tp rlctcr rliltr' tltt'tlrllt'tt'ttt't' itt tllt';ttt tlttt;tltptts
ttot'ltttllltllt ;rrrtl ,litrrrrlrllt Wt'tt'lt't l(| ()lll ltt'ltl rl()l(""lll(l
,rl /l
ri:number of samPles required:-;
/r,,, -,-rt 
tl-
r.r'here.r--standard deviation: { ttt_ |
For cxlttt't1'rlc. lcl trs
rll' crlvrltr.' ltow ls !'irt'tt
DETERMINATION OF SAMPLE SIZE 149
finc1 that we have measured the durations of six individual nocturnal howls as
follows:
5.2 s 3.1
6.1 7.2 mean:5.4 s
4.3 6.7
We calculate the standa rd cleviation (^s): I .5.
The tabular r value for live degrees of freedom (6-l) at the 0.95 confidence
level:2.51 I .
We decide to accept a 0.05 level of accuracy, then:
( 1.5)2 (2.51t)2 (2.2s)(6.6t)'_1tl
"- (5y'x01)5): - ((x)?) -- I -
Thereflore, we must obtain 212 samples ol nocturnal coyote howls in order to have a
reasonable estimate of the true mean duration. We would have to make the same
calculations based on a sample of cliurnal howls.
If you are unable to obtain an estimate of the variation to be expected in the
data, then you should err on the side of a sample size which may be larger than nec-
essary. Stuti.stit'.t estintute poptrlution purumetcr.s.fiurtt suntple nlcdsurcnterit.r'; there-
lbre, the larger the san-rple size, the better the probability that the sarnple statistics
will closely approximate the population values.
You can also determine the necessary sample size by solving lor l/ in power fbr-
nrulas lbr specific statistical tests. Power lormulas lor two t-tests are described in
Cliapter I I ; otl-rers can be lbund in various texts (e.g. Cohen, 1988, Zar, 1984).
You should not attempt to increase the sample size by increasing the number of
observations on individuals already in the sample and then pooling those 'k'obser-
vations on'rr'individuals to create a larger sample size consisting of 'ni'observa-
tions; this is 'pseudoreplication'(Hurlbert, 1984) or the 'pooling fallacy'(Machlis er
rrl.. 1985) which increases the probability of committing a Type I error.
Increasing sample size is not the only way to increase the power of your experi-
nrcnt (sec cliscr"rssion of power in Chapter I l). For example, Still (1982) has pro-
poscrl scvcral ultcrnatives to consider including: I. selecting a better experimental
,lcsign. 2. rrsing u lirrgcr alpha level (section I L5): and -3. secluential rnetliods.
7 Experimental rese arch
In the previous chapter, description and experimentation were discussed relative to
designing a research project. Description is the approach which uses naturalistic
observation in order to construct an ethogram for a species as it behaves normally.
In experimental studies, we test hypotheses about the relationships between inde-
pendent variables (individual or environmental variables) and dependent variables
(behavior units). We can either allow the independent variables to change naturally.
or we can manipulate them.
In addition, if we make a distinction between field and laboratory studies, we can
categorize ethological research along a continuum from descriptive field studies to
manipulative laboratory experiments.
The key difference between field and laboratory studiesis that, if everything else
is equal, descriptive studies are more valid when conducted under natural condi-
tions (i.e. usually the field), and experimental manipulations can best be controlled
under laboratory conditions. Nevertheless, it is sometimes difficult with certain
species to make naturalistic observations under field conditions. The researcher
should then consider whether natural behavior of the species can be expected, and
unobtrusive observations can be made, in a laboratory environment.
Even though we might want to shift our field studies into the more controllecl
captive or laboratory setting, some species cannot be easily and properly main-
tained in captivity. For example, Tinbergen, after reflecting on some of the short-
comings of his field studies on gulls, concluded:
It would seem to be more efficient to try to improve the lield methocls
than to try to keep a large colony of gulls under laboratory conclitiorrs.
f 
'l'inlrcrgctt, l95il ).5I I
Not only is it sometimes difficult to move fleld stuclics inlo thc lirborirtory. btrl
conditions in the field often make manipr"rlations vcry dillicrrlt. Al'ter rcviewirrl,
ethological and behavioral ecology stuclics ol'All'icun trngtrlirtcs. l.ctrllroltl (lt)l'/l
concluded that.
Ilxperirncnts htrvc rlrrcly bccrt t'rrt't'ictl orrt so llrt. Plrtllv lrt't rrusr' tnttt'lr
tlcscl'iPtivc wot'k wirs t('(lttitctl rtl lirst. rrntl P;ttllv lrt't'ltust'ol lltt'Plttrtt;rl
rlillit'rrllit's ol rn:uriprrllrlinl, srlrl urt1111 ,1,'r nl ('\l)('run('nl;rl .'tlu.rlt()n'-
f l,rrrlt,'l,l l't'i lil
THE VARYING VARIABLES
Research questions may require that measLlrements and manipulations be ma6e
in the field in order to be valid. This sometimes becomes evident when the same
experiments are conducted in both the field and the laboratory. As an example,
McPherson (1988) tested fruit prelerences of cedar waxwings (Bomhyc,ilta cedro-
rum) (categorized by species, color and size) in both the field and laboratory; the dif-
lerences were explained as follows: 'The lack of complete agreement between
prelerences for fruits in the field and in the laboratory suggests that factors impor-
tant in the field but controlled in the laboratory (e.g. abundance, location) override
preferences lor certain fruits' (Mcpherson, l ggg:961).
As a general rule, all ethological studies should be conducted in the field when
feasible; this is especially true lor descriptive studies and mensurative experiments.
Changing the emphasis of your research from description in the field to experimen-
tation in the field is a natural progression.
The observational work has to be lollowed up by experimental study.
This can often be done in the field. The change from observation to
experiment has to be a gradual one. The investigation of causal
relationships has to begin with the utilization ol'natural experiments.'
The conditions under which things occur in nature vary to such a degree
that comparison of the circumstances in which a certain thing happens
often has the value of an experiment, which has only to be refined in
the crucial tests. [Tinbe rgen, r 953; r 36 J
Descriptive studies and mensurative experiments in captivity, or the laboratory, will
likely be more efficient, but less valid than field studies. Likewise, manipulative
experiments should be carried out in the species'normal habitat when they can be
conducted in a valid manner. Neverthelcss, the controlled laboratory setting olten
plays an important role in ethological studies; several examples are given in sections
later in this chapter.
Peeke and Petrinovich ( 1984) can be consulted for another discussion of the rel-
Ittive advantages and disadvantages of field and laboratory studies in animal behav-
ior' Also. Mertz and McCauley (1980) present a similar discussion for ecological
stLrclics which can alsc-r be applicd to ethorogicalresearch.
7.t'l'lttr VAltytN(; VARIABLES
Ilre ohict'livc ol'ittt cx1'rct'irncttt is to test one, or lnore, hypotheses about the rela-
Itot15l1i11' lx'l\\'('('ll t';tl'ittltlt's. 'l'ltcsc nury bc cirusc-ancl-cll'ect relationships between
ttlrlt'Pt'tttlr'lll illl(l tlt'Pt'tttlt'ttt rtttitrlrlt's. ol'r'orrcllrlirlrr:rl rcltrti6ps5ipls hetwcc, i.de-
l)('ll(l('ttl t;ttlltlrlr's I lrt. rt'l;rlrorrslul)\ 11t\ lrt. l,,lr1, l(.11 (1.\,()ltrtirlrt:1.y ;lttl tlltlttgc_
ll('ll( )(rt :,lttrtl l('tilt(1tttr111rr,rl ('lr,rIlr.r ))
152 EXPERIMENTAL RESEARCH
Fig. 7.1 Interactions between an organism and its biotic and abiotic extcrnal
environment. Arrows indicate factors from the environment acting on the
organism and vice versa, (see text lor further explanation; drawirlg by Lori
Miyasato).
To understand which variables may affect an organism's behavior. wc must flrst
recognize that an incliviciual exists in time and space in a dynamic statc. contittttitlly
under the influence of its environment, continually imposing its tlwrl cllccts Llpoll
the environment, and behaving as a result, in part. of its evtlltttitlrlitry ittltl otttogc-
netic history. Figure 7.1 is a simplified diagram of'the relittiottship bctwcctl rttt
organism and the environment (also see Moclel. Chaptcr 2). T'hc cttvit'olttttcttl ltrts
both biotic (biological)and abiotic (physical) lclturcs. s()nrc ol'rvlriclr u'ill rrl'li't't tlrc
clrganism. Ascxlrlplcs. biotic lL.irtrrrcs rrlry inclrrtlc vcg,r'llrtion lyPe itt lr;rlrrl;tl st'lt't'
titll. iltclspccilic pretllrtor r.lli't'ts ()n l)rev lr,.'lltviot irtl(l ttlttltslrt't llit ('()tlll\llll)
sit,tlltls ott nurlt.st.lr,r'lion Alrroltt lt';rlttt(':r lllil\ lrr'ttttI,rt l;tttl ttt tt'1'rtl:tlllll' :l "l)('( l('\'
THE VARYING VARIABLES
temporal activity patterns, such as circadian rhythn-rs and seasonal cycles. That is,
temperature, humidity, wind and light levels may all be important in determining
the activity patterns shown by an animal or group of animals.
As discussed in Chapter 2, the organism's physical and behavioral phenotype
bears the mark of natural selection on the genotype over many previous genera-
tions. The phenotype includes the action and interaction of the genotype and envi-
ronment (including experience) and the animal's anatomy and physiology. The
organism can exert forces on both the biotic environment (e.g. intra- and interspe-
cific social behavior) and the abiotic environment (e.g. a badger burrowing into a
hillside).
Since all the f'actors in Figure J.l are variables that have a potential effect on all
behavior, the researcher must be judicious when selecting the one (or f'ew) variable
to study at any one time. The complexity of the interactions that can result from
two, or more, variables must be recognized and dealt with as skillfully as possible
within the limits available to the researcher (e.g. experimental designs in Chapter 6).
For example, Prinz and Wiltschko ( 1992) studied the eflf'ect of the interaction of
stellar and magnetic inlormation during ontogeny on the migratory orientation of
pied flycatchers (FicecluIu hypoIeut'u).
The first step is to list all the variables that are known to affect the behavior in
question or are suspected of having some effect. Some examples of the dillerent
types of variable are listed below:
I Environmental Variables
A Biotic
I Members of social group
2 Predator prey relationships
3 Vegetative characteristics of habitat
B Abiotic
I Temperature
2 Wind
3 Humidity
4 Cloud cover
-5 Topography
(r Tinrc circadian and seasonal
ll ( )r-grrnisntirl variubles
A ( icrrolyl-rc
I Scr
.) l'lrtr'rtl slrlck
ll l'ltt'ltol1'pt'
I llt'lr;rr tot:tl t lt tt;tt lt't t',ltt',
r53
EXPERIMENTAL RESEARCH
a Description of behavior (general categories, types, patterns and
behavioral acts)
b Frequency
c Rate
d Duration
e Temporal patterning-circadian and circannual
f Spatial characteristics
2 Physical attributes
a Morphological characteristics; e.g. shapes, color patterns
b Physiological characteristics
This procedure of attempting to list all the important variables is useful not only
when you are thinking about thepotential causation of a particular behavior in
anticipation of designing a study, but also when you have already decided on the
variable(s) you want to measure or manipulate and want to account for other poten-
tial sources of variation (e.g. eliminate or measure them). The number of variables
that could potentially affect a behavior is extremely large; therefore, the researcher
should be willing to spend time compiling the list. Important variables that you
overlook can olten be identified by other ethologists, therelore, you should enlist the
help of your colleagues in identifying other variables, as well as concurring on the
variables of most concern for measurement, manipulation or control. The impor-
tance of consulting colleagues is illustrated by Wehner and Rossel's (1985) account
of how Karl von Frisch came to make his dramatic discovery that bees use polarized
light from the sky as a celestial compass.
. . . two decades earlier . . . FELIX SANTSCHI had already observed
that ants could find their way even when they could see nothing but a
small patch of blue sky. In an interesting but unfortunately neglected
work . . .SANTSCHI ( 1923) literally asked the question 'What is it in
this small patch of sky that guides the ants back home?'SANTSCHI . . .
could not tell. In one experiment he had even used a ground glass disk
(which depolarized the light from the sky) and put it above a homing
ant. The ant instantly stopped and searched around at random, bttt
SANTSCHI did not draw the right inlerences fiom this importattt
observation. . . . After a quarter of a century had passed, in 1947. V()N
FRISCH did an experiment with bees almost identical to tltc cxl.rct'itllcttl
SANTSCHI had perlormed with ants. He got the suntc rcsttlt. itskctl tlrc
same question, and horriblc clictLr coulrl ttot tcll citlrcr'. Ilttlvcvct'.
VON FRISCH. thctr IIcarl ol'thc [)cparlrttcttl ol'Zoolou.y rrl lltt'
tlnivcrsity rll'(inrz. wlrs irr lr hctte r'position lo;ul\\\'('l sttt'lt t;ltt'sllotts
tlurrr SAN'lS('lll llrtl t'\,t'r lrt't'rr. Al orrt'ol lltt'ttt'\l l it('ttllv N1 t't'lttt1"'
Itr'lolrl lltr'slotY lo ltt'.tt,llt';tt'll('()l llrt'l'1tr.'11 " l)t'|;ltltllt'ttl 
ll'\NS
THE VARYING VARIABLES
BENNDORF. The physicist advised him to check lor polarized light.
Next summer, in 1948, VON FRISCH did the crucial experiment: He
placed a polarizer above a bee which performed its recruitment dances
on a horizontal comb, and as he rotated the polarizet the direction of
the bee's dances changed correspondingly (VON FRISCH 1949). This
was the first demonstration that an animal used skylight polarization
for adjusting the direction of its course. I Wehner ancl Ro.vsel, 1985. I 3 J
Alter identifying the variable of interest, the usual procedure is either to manip-
ulate that variable systematically, as von Frisch did with light polarization, or to
lollow it through natural changes, measuring both the variable and the behavior of
interest. The other variables you have identified as potentially having an effect must
remain constant or vary randomly, so that they can be considered to have no sys-
tematic elfect on the behavior being studied. The variable being manipulated is the
independent variable (e.g. light polarization), and the behavior being measured is
the dependent variable (e.g. orientation of the bee's waggle dance; see Chapter 6 lor
a further discussion of manipulating variables).
Several variables may be manipulated and/or measured simultaneously in order
to determine both individual effects and interactions. Selected analyses of this type
are discussed under multivariate analyses in Chapter 16.
When planning your experiments, always keep in mind how the various results
will (could be) interpreted.
Bourbon on the rocks, scotch on the rocks, vodka on the rocks, gin on
the rocks all can make you drunk must be the ice cubes.
IV. DeGlrett pers. commun.J
1.t.1 Natural variation
The first step in experimentation is to obtain clear descriptions and definitions of
thc behaviors to be measured (Chapter 4). This requires obtaining those descrip-
tions from secondary sources (Chapter 4) and/or making your own observations of
tlre behaviors under conditions of naturally occurring changes in the biotic and
rrl'riotic environment. Even if you use descriptions and definitions from other
rcscarchcrs, you should still gain experience in observing the behavior before con-
tl trct i ng cxpcrinrcnts.
Mcnsru'irlive cxperiments make use of natural changes in the environment to
\ru(ly thcir clll'cls on tlrc bchavior of selected species. For example, Pengelley and
,\snrrnrtlsorr (l()71) rlcrnonstnrtctl that thc yearly activities of golden-mantled
1'rrrrrrrtl stlrrrrt'ls (,\,1tt't tttttltltilltr,s lrttt't'rrli.r) lltrclttitlctl itt syttchrony with climatologi-
, ;rl vlrrr;rlrlt's nt tlrt' r'rrr,'irt)nnr('nl l'irrtf ittl' rrt'livrtV rll' thc tttlctttrItttl bcc
l,\'1t11,',,,,1,,ti,t:lttt lr'\ttntt) rurs sltorrtt lr1 trr'tlor'1 1l()(r/) to llt' llttsctl olt tltc lttttltt'
156 IlXPER I M ENTA L R ESEARCH
cycle. Sunrise and sunset apparently trigger the onset and cessation of activity in
cottontail rabbits (Srlvilugu.; .floridunu.r) and snowshoe hares (Lepus unrarit'urtu.s)
(Mech et u1.,1966).
Some enviroumental lactors fluctuate within seasonal ranges but vary somewhat
irregularly from day to day. For example, decreasing light levels near sunset appar-
ently trigger the initial departure towards the roost of loraging starlings (Sturnu.s'
vulgaris; Davis und Lussenhop 1970). Nisbet and Drury ( 1968) compared nleasure-
ments of the density of songbird and waterbird migration to l9 weather variables in
the area of takeoff. They lbund that migration densities were significantly correlated
with high and rising temperature. low and f alling pressLlre, lclw but rising hurmidity,
and the onshore component of wind velocity.
The response of animals to simultaneous variations in the environrnent can also
be studied. For example, Heinrich (l9l I ) examined the leeding pattern of the cater-
pillar (Munclu<'tt.sr,,r/rr) ancl fbund that it was consistent for given leaf shapes and
sizes. Simultaneous variation has also been the basis for many field studies of
habitat selectiort. MacArthur (1958), for example, studied the distribution of five
congeneric species of warblers while they fed on individual white-sprllce trees. He
clivided the trees into l6 zones ancl measured the percentage of the total number of
seconds of observation and the percentage of the total observations for each species
in each zone. He lbund that the five species distributed themselves on the trees such
that utilized dilferent microhabitat variables (FigLrre 7.2).
The age and experience of the animals under investigation can be allowed to
advance naturally and their behavior observed at various stages. Scott and Fuller
(1965), fbr exatnple, observed the changes in behavior ol several domestic dog
breeds from birth to maturity and were able to divide their development into fbur
periods: neonatal, transition. socialization and juvenile. Development of behavior
in the song span'ctw (11[clospi:tr mclotlitL) was divided into six sin-rilar stages by Nice
(1943). Drori and Folntan(1967) showed a marked elfect of experience on tlre coplr-
latory behavior of male rats, and Carlier anci Noirot ( 1965) demonstruted that expe-
rience improvecl pup retrieval in female rats. Stefanski ( 1967) slir>wed that the
average territory size of black-cappec'l chickadees (Prrru.r utricupillu.r) r,'ariecl cluring
six stages of the breeding season: prenesting, nest building, egg ltrying. incubation,
nestling. and fledgling.
The use of natural variation has limitations which are both clualitativc arrrl cprirrr-
titative. Waiting lor the proper conditions to arise' ancl atternpting to gltlre r ir sulii-
cient number of observations st'rt'netinrcs clrivcs thc cthologist to rrrtilicirrl
manipulation:
Systcntittic erltlrlitrrtirln ol'srrt'lr rtrrtrulrl t'xlx'riln('lllsllr:rl r\. \\\l('ntitlt(
r'()t)tl)irtisort ol tltt'stltt;rli()n\ \\'l)it'lt rlo trrrrl lltost'r\lrr, lr,l,) n()l tt'lt';rrt';t
t'tt't'tt t('Sl)()ll\(' t;ttt lrt'ltltllrtsl ll\ l'()(,rl tlr ;rl,ttltt,',1 r'\lrt'l ttttt'ttl'. lltt'
Fig' 7'2 Cape May warbler lecding positions. At least 50'2, ol'the actrvity is in the stipplerJ
zones. Each branch was divided into threc zones: B bare of lichen-covered base.
M. olcl ttcedles; and T. Itew (less than L5 years old) needles and bucls. (fro1t
MacArthur. l95tl).
ttt-t1lt>rtittlt thing seents to t-ne is not to miss the natural experiments anci
yct to know when it becomes necessary to continue by planned tests.
ITinbargcn, 1955;259J
i.t.z Artilicial ntanipulation
''\ttolltt't t'tPt'tilttt'ltlltl lt1'rlttrxtclt trl thc sttrrlv tll'cirrrse arrcl etlect o{'behavior is to
l:tkt't'ottllol ol lllt'v'ltt'iltllles:tttrl tnlrrriprrllrtr'llrcnr irr thc Iiclrl rlr the labrt*tt.ry.
.\lllt()ttl'lt llrr'rrrlilill)ltlitltr)lt t\;illtlt(.t;tl. t.rcrY lrllt.nrgrl slrorrlrl lte rrrlrtlc t() lll)l)t.()xi-
ttt;tlr'lltt'rr,tr ttrtrl.,lrtrttrlt;tttrl llrt,n,tlut,tl, 1r,rrr1,,..,,r., t 1o,.1.11 :rr Por:iltlt,.
THE VARYING VARIABLES
Percentage of total
number (2589)
of seconds of
observation
Percentage of total
number (80)
of
observation
151
,?i::{1 kr
3.8
3.8
20.6
2
8.3. \h
--21
t-11 2
4
3
0.5 /.il \\\
5.0
-1.2
4
li/'/ / I t",'*)
5 /.",'
B trl\
3.56 3.7
t58 EXPERIMENTAL RESEARCH
7.t.2t Elimination, disruption and manipulation
When manipulating the animal or exogenous stimuli to answer questions about
'how'an animalperlorms a behavior there are dilferent levels of intervention which
lead to differing degrees of validity of results. For example. in determining the
exogenous stimuli and corresponding sensory systems (or endogenous stimuli and
corresponding hormonal/neuronal systems) involved in a behavior you can elimi-
nilte, di.>'rupt or nrunipulate variables. These interventions (all of which are usually
referred to as 'manipulations') can be made on the stimuli or the animal's anatomy
(e.g. sensory system). Elimination, disruption and manipulation represent
decreased levels of perturbation, respectively; in general, manipulation provides
more rigorous and valid results than does elimination or disruption (see exan-rples of
bird orientation/rnigration studies later in this chapter). When stimuli are manipu-
lated (e.g. von Frisch changing the plane of polarized light received by a dancing
bee, p. 155), you can make predictions about the resultant behavior (e.g. orientation
of the bee's dance will track with the changing plane of polarization); that is. you
can invoke research and statistical hypotheses with higher resolution and greater
statistical power (Chapter ll). With elimination ancl disruption you are only
attempting to eliminate or disrupt the behavior being studied (often in an unpre-
dictable manner). For example, in attempting to locate the circaclian pacemaker it
was known that surgical ablation (elimination) of the suprachiasmatic nucleus
(SCN) in the brains of mammals eliminated overt behavioral rhythmicity; those
experiments provided sorne evidence lor the SCN being the pacemaker. However,
conclusive evidence was provided when Ralph et al. (1990) conducted transplanta-
tion experiments with normal hamsters and a mutant strain with a short circadian
period. They demonstrated that srnall neural grafts fl'om the SCN of donor ham-
sters restored circadian rhythms to arhythmic hamsters whose own SCN had been
ablated; the restored rhythms always exhibited the period of the donor genotype,
normal or mutant (short).
If you eliminate or disrupt stimuli in order to determine their role in a eliciting or
orienting a behavior, the behavior may come under the control of other stintuli anrl
sensory systems. Thus, when the behavior does not disappear, or is not clisruptccl.
you could draw incorrect conclusions. Indeed. this is what occurrecl in c:rrly cxpcri-
ments designed to determine the environmental cues used for oricrrlulion by liu'rrg-
ing bees and migrating birds (Gould, 1982). For exarnple, if you wcrc an ctlrologrst
in the early part of the century and were interestecl in thc cnvironn.rcrrlirl errcs llt;rt
homing pigeons use to orient back to the hornc lol't. you rrrighl lr:rvc rlcsiltn('(l('\lx'l
iments to elimirtatc rlr rlisrrrgrt polcrrlilrl crrcs. ll'yott ltypolltr'sizr'rl tlrtl pi1't'ons usr'
thc strn its:l c()n)l)ltss rilttl tesletl llrt'nr ott rl!'r'rt'lrsl tl:rVs (ltt t'littttttrtlr'lltt'srilr ;rs rr
r'ttc). tltt'lli,'t'otrs rvrlrrlrl slrll lrlrvt'll()nr('(l ltstttl'lltt't'lttllr': ttt;r1'trr'ltr ltr'lrl:tr llrr't ttt'
THE VARYING VARIABLES
Since the pigeons homed successfully, you might harve concluded that they don't use
the sun as a compass and therelore hypothesized that they use the earth's magnetic
field. If you then attached bar magnets to their backs (to tli.srupt the magnetic field
around them), but tested them on a sunny day, they would still have homed, but this
tirne they would have been using the sun as a compass. Further, unless you recog-
nized that you should have been controlling more than one of the variables at a time,
you might conclude that the pigeons use neither the sun nor geomagnetic field as
cornpass cues. Even if you recognized your design error and proceeded to disrupt
their orientation by applying magnets and testing the pigeons on overcast days. you
would not have as conclusive results as you could have obtained by monipulatirzg the
variables and predicting the changes in orientation (see experiments clescribed in
section 7.3).
When you eliminate or disrupt an animal's sensory system you also run the risk
of affecting other anatomical and physiological systems which could be important
for the behavior(s) you are measuring. The lollowing story illustrates how attempts
to eliminate a sensory system can have additional elfects on the animal's behavior
and the researcher's ability to interpret results:
A zoology student had succeeded in training cockroaches, ernd he
proudly displayed the results of his long efforts to his professor.
He had his cockroaches fall in, and he gave them the command:
'Forward, march!'the cockroaches marched lorward. 'Column left!'
the student commanded, and all the cockroaches turned left.
The professor was about to congratulate the student on this
remarkable accomplishment, but the student interrupted him. 'Wait!'
lre said. 'l still have to show you the most important thing.'
The student picked up a cockroach from the last row, pulled off its
legs, and put it back in its place. Once again he commanded: 'Forward,
march!'
The cockroaches marched as before. except, of course. lor the one
without legs. 'Column left.'Again, all the cockroaches turned on
command. except lor the one that lay where it had been placed.
The prof-essor looked inquiringly at the student.
Thc studcnt said proudly, 'This experiment proves conclusively that
cockroaches hear with their legs.' I Eigen and Winkler, l98 I :298 -299 ]
I Itis lrrlc grvcs risc to three important questions: l. Was the manipulation appropri-
rrlt'lo obllrin vllitl rcsults'/ If so,2. Was this severe a manipulation necessary to
iurs\\'('r llre tescrrtclr tlrrcslirln'l Il'so.3. Wts the answer to the research question
rrorllr tturkinl llris s('verc lt tnlutipttllttiort'l Sincc thc rttrswcr tt> questions I and 2 is
'No', lrllr (':ur t ottt lrrrlt' tlr;rl llrt'slrttlt'ttl u'lrs t'illtcr rr rtlrivc or sittlistic rescarcher. If
\\r';'11t' llrr'rlrrrlr'nl llrt'ltt'ttt'ltl ,rl ,r',.,unutr1' lltt'1 \\('r('{rnlV tt:rivt'tttttl ittscttsillvc. wc
159
l6l160 EXI'ER I M ENTAL RESEARCH
should recommend that they answer those questions befbre making any manipula-
tion in their next experinrent.
Manipulation of variables (versus elimination or disruption) is the method being
employed when the researcher uses rnoclels and dummies. or conditioning (all are
discussed below).
7.t.2h Models and dummies
ll[ot{cl,t constructecito rnimic animals. or parts of animals. and tlumnzre.s (stutled
skins of animals) have a long history ot' use in ethology. Dun-rmies were used by
Allen (1934) in his study of the courtship of rufled grouse (Bortu,su wnbellu:; L.), in
Chapman's (1935) study of courtship in Gould's manakin (Murtucus vetellinus
t,ircllinu,t), and by Lack ( 1943) in his study of aggression in robins (Eritltucu.s rubec-
zrla: also see Table 8.3). Models and dummies have the advanta-ee of allowing the
experimenter to vary stimuli (e.g. visr-ral. auditory, chemical. tactile) in a systematic
way in order to measure the effect of qualitative and quantitative ditferences.
Tinbergen was an early and exemplary proponent of the use of models (Dawkins cl
u1.,1992).
As a typical example. Tinbergen and Perdeck (1950) presented models of an
aclult herring gull's head to herring gr"rll chicks. They fbund that the color of the spot
on the bill (qualitative property)of the nrodel had an eff-ect on the number of pecks
given by the chicks (Figure 7.3A). Tinbergen and Kuenen (1939) used simple
moclels to demonstrate that the gaping response of nestling blackbirds (Turtlu.s
nterulu nterula) and thruslrcs(Turclu.s ericetonnn ericelrtruni) is oriented by the rela-
tive size of the parent's head to their bocly (Figure 7.38).
Moller (1987) stuclied the role of badge size (extent of dark coloratiou on the
throat and breast) on status signaling in house sparrows (Pusscr tlonrcstit'u,s) by
placing stulfed male house sparrows (dummies) near nests. Stout ancl Brass (1969)
placed pairs of dummies, or wooden-block models witli tiltable boclies and
adjustable stuffed heads (Figure 7.4). in glaucous-wingecl gull territories: tlicy
demonstrated that the head and neck are the parts of the bocly that relcusc territol'-
ial aggression displays in this species.
Some researchers have incorporated movement ztnd/ot' ttclors lttttl stlttrttl irtto
their models and dummies. For example. Esch (1967) used et wootlcn. tt.totot'-tlt'ivctt
model in his research on communication ol'firod source locittion in ltortcybces. I lte
rnodelwas the approximate size ot'the honcybccs bcing sturlicrl. btrt it rlitln't t lost'll
resemble them physically: this probablv ltirtl littlc cl'll'ct sirtcc lltc cxlrerittt('lrls \\'('r('
carrieclttut in a tlark lrivc.-l-lrc rttorlcltlirl Ilrr,c tltc itle lrtit'rtl.,tlot rtl lltt'lttrr"s tltlrtlr
ititnls itnrl ltcrlirnut'(l ;t 'n()nltitl'n'lr1'1'1r.' rl;rrrt',.'. lrttl no lrt't's lt'll llrc lttrt'l,r:t';lr'lt lol
litotl itr llrc tltrr'( ll()n ptrrl l;lttttt'rl lrt lltt'ntotlr'l r tlrtttt t' l ',,1t ,,,tt, ltl,l,',1 llr,rl ',r)lll('
lir 71
THE VARYING VARIABLES
A. A cultlbtxrrrl n.roclelol a herring gull head being presented to a chick (adapted
l'r'onr'l'inbcrgcn l9(r0b by Lori Miyasato). B. Presentation of models of the
l)iucnl\'lrcrrtl. both'rrnrl tail to study the rc-lationships that orient nestlings'
lrrpirrl' r'esl)()nsc (ltlirp(ctl ll'ont Tirthcrgcn 1972 by Lclri Miyasato).
EXPERIMENTAL RESEARCH
Fig. 7.4 Models and a durnrny (2d; used by Stout and Brass ( 1969) in their study ol
glaucous-winged gulls. la, upright, threat-postured body 1b, trumpeting-
postured body; lc, choking-postured body; 2a, basic wooden model;2b, upright
threat posture; 2c, model without wings: 2d, dummy showing upright threat
posture with wings.
thing more than the dance was necessary to elicit foraging. More recent research
used a motor-driven model bee which not only danced, but also vibrated artificial
wings and exLlded sugar-water samples; this dummy bee was much more successful
in recruiting foragers (Mollett .1990).
Hunsaker (1962) used a head-bobbing machine to move the model heacls ol'
lizards (Sc'eloperu^r sp.) in dilferent species-typical patterns. He firuncl thiit l'emalcs
selected those rnodels which head-bobbeci in the pattent typical ol' thcir own spccics.
Jarvi and Bakken (1984) used three dummy great tits to str-rdy thc f'unction ol'tltc
variation in the breast stripe. Their dummies could be turned 360'. by radio cont rol.
to keep them always oriented in the direction from which tlre livc hirrls irpprolclrctl.
Models shor-rld contain the important f-eatures ol-thc livc irnirrurl. irntl tlrev
should be used in a normal context (see Cr,rrio 197.5 lirr an cxccllcrrt cxlrrrple ol
extensive and proper use ol'modcls). Irt olltcr wortls.';rrr rrrrtlerlying rrssrrrrrptiorr ol
the ntcthrttl is thlrt rcsll()ltsc to 1l19 tttotlcl tlcPcttrls ()ll r))u('lr lltt's;rtttt't';ruslrl slslt'nr
ilst'csll()llsclolltctt;ttttltlsttrrrtrltts'(l.ost'\'. l()77.).).1; llrrlor lrrn;rlt'lr llrrs;rssrrrrrP
titlttistlttt'lVr:tlirl;rlr'tl llttttr'\('r lnl,r:t'\''st'\[t'1g1111'1ll:.onllrt't,",1)on'.('ol lro',l lr',lr
THE VARYING VARIABLES
(Chocton aurign) to a cleaner (Labroides pltthrirophugus), he demonstrated the
validity of his use of a cleaner model through three indicators: pose duration, pose-
to-inspect ratio, and approach behavior of the host fish to both live cleaners and his
models.
Not only must the Lrse of rnodels and dummies be carefully planned. but the
results of such experiments must be carefully interpreted. As an example, in another
aspect of Tinbergen and Perdeck's (1950) experiments on the begging response in
neonatal herring-gull chicks, they changed the position of the red spot from the
model's bill to its forehead. The ohicks delivered significantly n"rore pecks to the
model with the spot on the bill than they did to the model with the spot on the fore-
head. They concluded that it was the position of the red spot on the head that
caused the decrease in the chicks'responses. Hailman (1969) re-investigated this
phenomenon by placing the rnodels at different distances from the pivot point of the
rod holding the model. Further, he adjusted the height of the chick so that it was
always at eye levelwith the red spot. He had created three models: a 'normal model'
with the spot on the bill, a model with the spot on the forehead and the pivot point
the same ('slow model'), and a model with the spot as on the bill-spot model ('fast
model'). The fast forehead-spot model received more pecks than the slow lorehead
model, although f-ewer than the 'normal model,'revealing the elfect of speed of the
red spot on the chicks'responses. Therefore, Tinbergen and Perdeck (1950) were
correct in concluding that position of the spot is important; but I{ailman demon-
strated that speed of the spot is also a contributing factor.
Models and dummies shor.rld be used with appropriate caution. They may be
either too simple with the inrportant stirnuli absent, or too complex with extrarleous
stirnuli confounding the experiment. As with any tool, however, in the hands of a
skilled researcher. models and dummies can be an important means of manipula-
tion in the field.
7.t.2c Instrumental and classical conditioning
An iniportant technique fbr manipulating variables in the laboratory is through the
ruse ol' instrurnental and classical conditioning. Conditioning is a powerful method
lirr studyrng 'cirus;ution' ancl answering 'how' questions; the basic paradigms for
irrstrtrrncntuI irntl classicaIconclitioning were discussed in Chapter 2.
('orrtlitronrng is thc busis lirr many psychophysicalstudies designed to determine
'lrrrw' rr spccics tliscrirninirtcs bctween varic'rus stimuli. For example, May et al.
( f ()lili ) strrtlit'rl lrorv .lrrprrrrcsc lnirca(l ucs ( lllttcuut.f ir.st'ulu) discriminate between dif-
lr.'tt'rr( ( ()() \ot;rliz;tliotts ltv ttsutp, itt.ttt tttttt'ttlttl t'otttliliottitt,q lct trairr inclividr"ral
lnir( ir(lu('s lo tlrst rrrnrr;rlt' \nroollt t';tr lr'' l;;1'11' ;trttl 'slt)orltlr llrtc ltiglt'ctlo sttttnds.
Ilrt'rrrrrt rr,lu('\ \\'('rt'lrrrrrt'rl lo nr;rk,'lt,rtt,lt o111:tr'l tt'tllt;t tnt'lrtlt'Vlnttlct itt I'csPottsc
164 F.X t'hlL l M E NTA L R ESE,ARCH
to one type of vocalization and release contact in response to the other vocalization.
First, generalization tests showed that the macaqLles responded appropriatelyto
both natural and computer-synthesized coo soutrds. Then acoustic f'eatures were
systematically removed from the computer-synthesized sounds to determine the
minirnal elements necessary lbr the macaques to recognize them as distinct coo
sounds. Pietrewicz and Kamil (1977\ studied the ability of blue jays (Ct'rzrnc'ittcr
t'risttrttt) to detect cryptic moths by instruntcntully t'onditiorting them to respond dif-
f'erentially to the presence and absence of moths in projected images (slides). If the
projected slide contained a nroth. l0 pecks on the stimulus key resulted in the blue
jay being positively reinfbrced with half a mealworm. The jays were able to detect
the moths, but their ability was allected by the background upon which the motl-t
was placed and the moth's body orientation. In a later study, Pietrewicz and Kamil
(1919) used the same in.slrruncntul cotrtlitioning procedure to stucly search irnage for-
mation in blue jays.
Often questions about 'how' an animal uses environmental cr-res begins with
studies of what a species'can'perceive (Miller 1985); that is, what stimuli they are
capable of perceiving and responding to. For example. Lehner ancl Dennis (1971)
hypothesized that waterfowlrnight use atmospheric pressure changes as a cue lor ori-
entation during migration. They used instrumcntul t'onditiortirtg to train mallarcl
ducks. in a barometric pressure chamber, to peck one microswitch when the pressure
increased and another microswitch when the pressure decrensed. They then exposed
the ducks to sequentially smaller changes in pressure and demonstrated that the
ducks could perceive atmospheric pressure changes as small as 0.4 psi. Kreithen and
Keeton (l9l4a) used r'lrr.r'.ricul t'ontlitioninglt-t test the capabilities ol- homing pigeons
to detect atmospheric pressure changes. The procedure was to place the pigeons indi-
vidually in an airtight cl-ramber. change the pressure over a 5 second irrterval(neutral
stimulus), hold the pressure steady lbr the llext 5 seconds, and then deliver electric
shock (r,rnconclitionecl stimulurs) to the pigeon. causing the heart rate to incrcusc
(unconditioned response). After a f-ew presentations, the pressure change becullc it
conditioned stirnulus that caused the heart rzlte to increase (conditionctl t'cspottsc)
without the electrical shock being adrninistered. Then, the pigcons'pcrccption ol'rlil-
ferent amounts of pressure change was determinecl by observitrg chungcs irt tltcir'
heart rate. They determined that the homing pigeon is ahle to tlclcct ltttttospltct'it'
pressure changes of l0 mm of H,O. or lower. Kreithcn iurcl Kccton ( 197-lh) ttsctl lltt'
same r'1a.ssit'ul t'ontlitiottittg procedure to detcrnritrc thc ability ol. ltotttiltlt pigcotts lo
detect polarized light. a cue usecl by bces itt ot'ictttlttiott.
As part of thcir rcscarch oll coyotc 1'rrctlrrliort. llont lrrtl l t'lrtt't (lt)i.l)rr;tttlr'tl
t1r clctcnlinc tltc lrlu'csl ctt'u ilontnt'rtl,rl lilltt lt'rt'ls llt;tl t'ovolt's. tt lrtt lt lttttrl ;)ttnt:ll
ilyirl rrip.lrt.erlttltl Pt'tt'rrvr' ('rr\'oli's\\('rr'n)(lr\rrlrt,rlll ll;rtttr'rllo',l,ttttl ttt rt,l.ttL 1,"'l
t'l11rtnlrr'r (l'i1'rrrt' / r)iilr(l lltr't';r rlrrrrrtlrt', lr1'lrl Irrllt't lt'rl ()tr .tn ill).t(ltrt' 1rl.r',1t, ,lt'1.
THE, VARYING VARIABLES
Fig. 7.5 Coyote in tcst chambcr uscd by Horn and Lehner (1975) to dctermine the
coyote's scotopic (clirrk aclaptcd) light scnsitivity. A stinrulus patch is at the
coyote's eye level at the ccnter ol the right wall; it is not illuminated in this photo.
Two loot treadles Are on the floor, separated by a plexiglas partition.
at the coyote's eye level. They were then instrumentally conditioned to step on a foot
treadle to their right when the light was on. and a treadle to their leli wlien it was ofl.
Once they consistently perlbrn-red this discriminzrtion task, then intensity of tl"re
light stirnulus rvas pr"rt under the control of'tl-re coyotes. When they stepped on the
right lbot treadle (indicating they could perceive the light stimulus), the light auto-
ruatically decreased in intensity: conversely. stepping on the left treadle (indicating
they cor-rld not perceive the light) ar.rtomatically increased the light intensity. The
irtterrsity ol-the light stin-rr.rlus was continuously recclrded resulting in a graph of the
coyotcs'psychophysicaI threshold lbr vision at nigl"rt.
Ittstt'untcrttal contlitioning has bc-en an irnportant technique in studies of forag-
rrg sl nrtcgics. As ittt cxanrple. Har ct a/. ( 1990) irt.strLunentully t'ontlitioneclcaged gray
i;rvs ( /'r'r'i lr tt't'tr.:' r'trnttrlt'l,rn') to altcrnate hclps on two perches in order to receive fbod
;rellcts. l'lrc irrvs corrltl lirritgc in two'lirod patches', each of which had two perches
;ttttl :t pt'llr'l tlispt'nscr (liigtrrc 7.(r). Thc tirod pellets were delivered on variable ratio
',t'ltr'tlttlr's (\11(. sr'r'('1t;tptct l) irr botlr 1'rirlcltcs. l}trth VR scherlules hac'l the salne
ttt(';rtt(r'l' ntt';tll ()l ,l01lr'tt'lt ltops Vl{.10). l)ul ()nt' plrlclt lrirtll high vitriirnccabclut
lltt'tttr',ttt:tttrl lltt'o(lrt't ;t lr)\\ \ittl;lltr'r' Ilrr't'r;1 1;tf : t'l)psr'ttl lilt'ltt]c 1t;ClcpClfliif lly
rtt lltt' lrry'lr r,u r,ln( (' lor rtl P;rlt lr
r65
ill
I
161
166 EXPERIMENTAL RESEARCH
Perch InPut lines
Fig. 7.6 Diagram of the instrumental conditioning apparatus used to study gray 
jay
loraging strategies. The two patches each consisted of two perches attached to
microswitches, a hole through which clispensed pellets were reached' and an
automatic pellet dispenser. A microcomputer recorcled perch hops and operated
the feeclers. as well as controlling lights ancl backgound noise (from Ha et ai''
1990). Copyrighted by Academic Press'
Laboratory research using classical or operant conditioning provides the oppor-
tunity to manipulate variables very precisely and measLlre the animal's resultatnt
behavior very accurately. The drawback is that we don't always know how tcl tritns-
late these laboratory results into what the animal actually does in its normal crlvi-
ronment. We only determine what the animal'can'do; we are not sllre whethcr tlrirt
is'how'they normallY do it.
If you are interested in more detailed inlormation ttn spccilic cotltlitiottittpr
methods, you should consult the primary literature tbr papcrs rcpot'tittg otl t'esertt't'lt
similar to what you are planning. Also, there atre scveralgoocl tcxt books otl lcrtrtlitll'
and experimental psychology that present the basic Itlctltotlology (c'8 1)ilvcv' l()S I :
Iverson and Lattal, l99l ).
EXAMPLES OF EXPERIMENTAL MN NII'IIT-ATION
7.2 F'URTHER EXAMPLES Otr EXPERIMENTAL
MANIPULATION
7.2.1 In the field
Many experiments arise from descriptive studies in the field and progress through
mensurative experiments to artificial manipulation of the animal and/or its environ-
ment.
7.2.ta Manipulation of the animal
Manipulation of the animal involves altering the anatomy and/or physiology of the
animal (A and P in the model in Chapter 2). For example, the role of sensory recep-
tors and physiological state can be studied by manipulation of the animal per se.
Layne (1961) studied the role of vision in diurnal orientation of bats (Myotis' uus'-
troriparius) by releasing normal, earplugged, and blinded bats (two types of sensory
elimination) at various distances from the home cave. None of the eye-covered bats
homed, suggesting that vision is an important in homing behavior. Ehrenfeld and
Carr ( 1967) measured the role of vision in the sea-finding behavior of lemale green
turtles (Chelonia m1,das) by blindfolding them or fitting them with spectacles con-
taining dillerent filters (elimination and disruption of the visual sense). Blindfolded
turtles and those wearing red, blue, and 0.4 neutral density filters had significantly
reduced orientation scores.
Morphological changes are occasionally made on animals in the field, and the
effect on the animal's ability to obtain and/or retain a mate, social status or aterri-
tory is then measured. In these studies, it is the change in behavior of other individ-
Lrals that engage in interactions with the altered individual which is usually being
rneasured; but an ellect can also often be found by observing the altered individual.
As an example, Bouissou (1912) showed that dehorning and reduced weight
tlecreased the ability of domestic cattle to obtain and maintain high social rank in
the herd. Harris sparrows (Zonotrichia quereula) signal their dominance status by
variations in the amount of black leathering on their crowns and throat. Rohwer
(l9l1l rankecl individuals into 14 'studliness' categories (Figure 7.7) and then
rrltcrctl thc unrount of black feathering on selected individuals to determine the
elll'ct orr thcir status. Subordinates dyed to mimic the highest ranking birds were
still pcrsccrrlctl l'ry lcgitimate'studlies,'and bleached birds eventually exerted their
rrornurllv lrrglr-rrrrking tlorninrtnce. The data suggested that 'cheating' (i.e. lower-
rrrrkinllrrtlslreirruelcv:rlcrl instatrrssinrplybyhavingaclarkercrownandthroat)is
'.,,r'rrll\ t onlr,rllctl Molle r'(l()li7) rrsctl sirrrilru' ttltrtipulittions itnd demonstrated a
',1.rltrr rtltr;rltttr'' lttttt'liott lirt lrlttl,'t'stzt'(tllttk r'olot;tlirlrt olt llttrxtl irtttl brcitst)in
ft,,tt',,'',1);tt t(ltr'. ( /ilr \t r rlrtrttr'\//{ r/\)
hXAMPLES OF EXPERIMENTAL Mn Nll'trt-ATION
The role of the red epaulets of male red-winged blackbirds (Agcluius phoeniceus)
was studied by D. G. Smith (1912) by dying the epaulets black on selected territorial
males. He lbund that the epaulets were important in maintenance of territories
against rival males, but they had little eff-ect on the males'ability to obtain mates. N.
G. Smith (1967) changed the eye-ring color of one member of mated pairs of sym-
patric glaucous gulls(Lurus hyperborea^r), Kumlien's gulls (L. gluuc'oirlc.r) and herring
gulls. In all cases where the female's eye-ring color had been changed the pair broke
up. but alterir-rg the male's eye-ring appeared to have rro ef-fect on the pair's behavior.
It is important in all research where animals are manipulated and the elfects are
studied in interactions with other individuals to observe the ellects on the manipu-
lated animal, as well as on others responding to it. This is true in both intra- and
interspecific studies, such as the effects of altered rnales on selection by females and
altered prey on selection by preclators.
7.2.th Manipulation of the envintnment
Altering the biotic or abiotic environment (see section 2.3.2b) in order to study its
resultant eftect on behavior ranges from gross-perturbation experin-rents to subtle
changes in one clr a lew stimuli.
Stewart and Aldrich ( l9-51 ) were able to get an indication of the extent of the
surplus'floating'population of unmated rnale birds the spruce fir tbrests by drasti-
cally reducing (by shooting) a large number of territorial holders on a 4O-acre tract.
During nine days in June. they removed 148 territorial males, reducing the popula-
tion to 19"/,, ctl the original. They continued to shoot birds as they moved into the
area. and by July 8 they had collected a total of 455 individuals. This is a rather
drastic perturbation experinrent, and as they adrnit 'the breedin-u territories were
completely disrupted durring the period when the original occupants were being
rernoved and at the serme time new adult males were constantly invading the area'.
On a smaller scale, Krebs ( 197 I ) shot six pairs of great tits occupying territories and
observed thitt residents expandecl their territories ancl fbur new pairs took up occu-
pancy. In contrasl to these major manipulations. Tinbergen was prone to concen-
lrate on srrbtlc environrncntal changes in order to study ef-fects without greatly
tlisturbing llrc nornralactivities of the animals.
'l lrc trick is. to insert experiments now ancl then in the normal lif-e of the
:rrrirrurl so tlrat this normal lif.e is in no way interrupted; howeverexciting
tlrr'rrstrlt rrl'l lcst nriry bc lirr us. it must be a nratter of daily routine to
llrr';rrrirrrrrl. A rrurrt u'lro lrrcks thc lccliltg lirr this kind of work will
nt('\ llltlrlV t'onttttit ollt'ttst's ittst ;ts s()ltlc l)c()lllc citttttttt help kicking and
rl;rrn,rr'urt'tlt'lrt;rlt'llrtntlur('urir t()r)nl \\illtottl e\en ll()ticirrg it.
f l'tttl't t..t"'tr. /(i-5-i /-i'\/
169
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EXPERIMENTAL RESEARCH
EXAMPLES OF EXPERIMENTAL MAN II'III-ATION
importance of the various configurations in releasing egg retrieval was l.
largerlsmaller;2. speckled>not speckled; 3. greenlblue, red>grey; and 4. shape,
other than roundness, was relatively unimportant. The titation method used by
Baerends and Kruijt is worthy of careful consideration lor other studies using
models. This method allowed them to rank the models on a relative basis between
and within the four categories of features.
Our experiments with the size series showed position preference to be a
quantitative phenomenon. A first choice for the smaller egg in the
preferred position can always be overcome by increasing the size of the
model in the non-preferred position. With our series of models
gradually increasing in size it was possible to identify stepwise, in
successive tests with the same bird. the minimum size of a model
required to overcome position preference, when in competition with a
dummy of a smaller size in the preferred position. Thus, through this
'titration,'a model was lound the value of which. in combination with
that of the non-preferred site, could just outweigh the combined values
of the smaller model and the preferred site. Empirically it turned out
that the birds were acting in accordance with the ratios between the
surlaces of the maximal projections (maximal shadows when turned
around in a beam of parallel light) of the models. Different pairs of
models, matching each other with respect to other parameters tries (e.g.,
volume), or equal with regard to the dillerence instead of the ratio in the
parameters used, proved to be unequal in counteracting position
preference. The ratio between sites olten remained constant for a couple
of hours, and within that period the relative value of dummies with any
kind of stimulus combination could be measured and expressed with
reference to the standard size series. IBaerand.s ancl Kruijt, I973:30J
Baerends and Kruijt's results (Figure 7.9) show how the releasing value of a
rnodelegg with respect to size is affected by the other manipulated variables, such as
changing the egg shapes into a round-edged block, omitting the speckling on brown
rnodels. ancl adding speckling to green models. Baerends and Kruijt caution that the
cxactitucle ol' the method should not be overestimated. It was limited by the step
sizcs in tlrc'titrittion'series, and there was considerable variability in the results of
inrlivirlual 1csts. However, it is clear that their 'titration' procedure provided
irrcrcirscrl turrlcrst:rnrling of the role of the various stimuli in the egg retrieval behav-
ior'. Also n()lc lhrrt thcy conclucted over 10000 tests in theirexperiment.
Mruriptrlrrtiorr ol' cggs. irltlrough consiclcrecl here as an intraspecific manipula-
Iron. rnrl'lrl lrr'lrrl'11gi1 lohcrttlrrtilrrrllrtiortol'tlrcbioticcnvironment.Theanswerlies
tn lltt' ('\('\ ol llrc lrt'ltolrlt'r'. lltt'1'ttlls. lrt'ttt t'trr"ll ptoh:tbly ttcvcr bc sttre.
,,\n rrtlr'r tltr'r rltr tnttntl,ulttttr,r/ \\,r" ttt,t,l,'l,t I rlllt';olttt;tlttl M:ttlirr (l()(r9) in thcir
r:1 .3
b
r:1 .5
c
r:2.3
d
r:1 .3
t
r:1 .3
I
I
66606@
@666@@
X>:8 r:1.3 X: <1O r:1.7 r:1.3
F-ig. 7.8 The'tritration'methocl lor determining the value of an egg model' 
The circle
represents the nest with one egg in the nest bowl and two models on 
the rim' The
code numbers 7 to 12 refer to the models of the size seriesR' x is the model 
to be
measured: r is the ratio between maximal projection surfaces of the model on 
the
nest rim. The black model is the preferred one. I, determination of the value 
ol
the position preference. In Ia the right side is pref-erred. This preference 
remains
when model 8 is replaced by the smaller model 7 (lb), but can be overcome 
by
replacing 8 by 9 (lc); this sequence shows that the value of the position 
preference
lies between r =1.3 and r = 1.5: this conclusion holds when another 
pair of
dummies with the same ratio is used (ll). control test le shows that the size
optimum for this gull exceeds size I l. II, determination of the value of model x'
Tests IIa. IIc. and IIf show that the position pref-erence has remained unchanged'
Test IIb and IId indicate, in combination with the preceding and succeeding tests'
that the value of x is between those of models 8 and l0 0f the reference size
series (from Baerends and Kruijt' 1973)'
Manipulation of the environment can be conveniently divided into fbur types:
intraspecific, interspecific, other biotic factors, and abiotic environmcntal 
mitnipLt-
lations. The intraspec'ific facihtating effect of a female mallard 
(Atru's plut.t'rht'nt'lttt's\
on male courtship clisplays was demonstrated by weidmann ancl 
Darlcy ( 197 I ) by
introducing a strange female or male to resident groups clf threc 
nlttlcs in thc sp|irtg
and autumn. Free (1g61)manipulated the bioti( cnt'irttnnturl itt horlcybcc 
ltivcs lttttl
showed that the amount of pollen collected increasccl with tlrc lllll()r'llll ol' 
ht'orttl
present and decreased in the absencc tll- it cltlccll. Ilc wcrtt olt to isollttc s()lllc 
()l tll('
stimuli proclucecl hy thc brotltl which irrc inrPorllrrl irr slirilttl;tlirrp, llolle 
rl t'ollt't lt.tt
Illrcrcrrtls irrttl Krtriit (l()71) tlef el'tttittetl lltt trtlr'rr tltt't if tt' stitllttlt lllll)()ll;ttrl 
ttt
r.clelrsirrl,(.1,1,. t('ltit'r';tl itr llt'ltittl'1'ttlls lrl ptt'st'ttltttl'lllt'ttt rt'tllr llttt't'tlllll('tl\l()llill
tttrttlt'l t'1'1"' l)lttt'tl lrtt',rl 't ltltl('r)ll llrt't'tll't'dl 't tlt"'l 
(l t1'rll' / )'11 llrt'rt'l'rltrt'
2.O log. cm!
Model value -*
172 trX l'trlt I M EN TAL R ESEARCH
R series
ffi bto*n
l:lEl grccn
Fig.7.9 The averagc valucs tound l'crr various models rvith respect tcl tlte relcreltce 
size
scries R (standarcl brown. speckled models). The position ol dillerent types ol'
mgclel (brow1. speckled. block-shapcd (a)l brown' urtspecklecl' cgg-shapecl 
(b):
green.unspecklecl,egg-shapecl(c):green'speckled'egg-shaped(d)'eachin
dilllrenl sizes. was tleterminecl with tlre rnethocl clescribed irl the legend ol' Figurc
7.8. The cocle numbers 4 to l6 stand fbr respectively' 4/B to l618 of thc linear
dimensions of the lrormal egg size 1$ = 8/8). Thc Irarintal prolectiorl sltrfaccs of
thc. eggs of the rel'crencc series have bec'n plottcd (egg centcrs) alclng the
logarit|mic scale (cmr)ol the abscissa' Equal distances bctweetl poittts ou this
scaleimplycqttalratiovalttes(lrclmBaererrdsandKruiit'1973t.
study of acoustic interactiot-t between tw'o syrnpatric species tlf 1'r'og. ['sttrdttltltrvtrt
,scrrtirturrntrtrutu and C'riniu Iit'lorittnrt. They played a tape-recortlctl rllatitlg 
cttll ol'
C. t,it,trrittrru ancTsynthetic signals to individual calling rnalcs ttl' l'. .st'rttirtt(tt'tttor(tl(t'
The call ot'Cl yir'10 riuttu.if played above 80 t1B. ancl synthetic pulsctl sigrtitls 
rt'itlt;t
carrier t'requency of 1500 to 2500 Hz. were all efl'ective in inhibiting /i ,t't'tttitttrrt'
nlorutu males from caliing.
Munipulution 0f'tltt,ern,it0ntn('nt clttl.take matry lilrtlls. Tw'o bitslc Pttrcctltttt's;tlt'
oftenusecl: l.changetheenvinrr-rrnentinwhichthcartirtrtl is1'rt'cscrttlvlot':ttt'tl'.t '
relt.,catc the a,i'tirl t9 1161lrcr clvirtlrrrrrcrrt. l'lrcsc 1'lt'ttcctlttte s ltlt' l't'ttt't;tllV tt:t'tl l"
clctcr,ti,c thc clll'ct tll' tlrc trl'liotic lttttl/ot lliotit' (t'.1'. r('l'('l;lll()ll) ('ll\ ll()lllll('lll
Ittlrvcvt,l.. tltr't.ottlotttttltttl t.llt'tls ol ittlt;t inr(l rrll('tr;rt't tll( llll('l:l( ll()ll" ill( 
()ll('ll
tlittit'trlt lo i'ltttttlt:tlr'
EXAMPLES OF EXPERIMENTAL MANII'TJLATION
B
Fig.7.l{) Digger wasps memorize the landmarks around their burrows in order to find
them when they return from hunting. To test this, Tinbergen (1972) arranged a
circle of pine cones around a burrow (A), and the wasp memorized it. When the
circle of pine cones was rnoved a foot or two, the wasp looked for its burrow
within the pine cone ring (B). When the pine cones were arranged in a triangle.
and rocks were arranged in a circle, the wasp looked for its burrow in the circle of
rocks, demonstrating that it was the geometric configuration (circle) it was
remenrbering, not the objects (pine cones) (drawing by Brenda Knapp, based on
Tinbergen, 1972).
Tinbergen and Kruyt ( 1938) investigated the role of landmarks in the ability of
t-emale cligger wasps (Philunthus triungulunr) to locate their burrows. They manipu-
lated the type and geometric arrangement of objects around or near the burrow and
recorclecl thc response of the returning wasp (Figure 7.10). This is typical of the
simple, yet cogent. type of experimentation lor which Tinbergen is famous.
Iternarking on Tinbergen's methods, Lorenz (1960b:xii) stated, 'He knows exactly
how to irsk cprcstions of natlrre in such a way that she is bound to give clear answers.'
Pe r tlcck ( I 9.5[J ) rclocated migrating starlings (Sturnus vulgoris) geographically to
nrcirsurc tlrcir rrbility to nuvigate to their normal winter areas. He captured adult and
irrvcttik'slrrrlirtgs irr'l'hc Ncthcrlunrls tluring their south\,ry'estward falln-rigration and
I r :utsPor lctl llrr'rtt sorrl lt lo S'uvitzcr lirntl wlrcrc thcy wcre rclcasecl. Aclults were recov-
t'tr', 1 n,rtlltrvt'sl ol lltr'rt'lr'rtst'sitt's itr lltt'tt notttt;rl u'ittlcl'lll'clts itlong thc crlrtst ot'
Wt'rlt'ttt I ttt,,1rt' I lrt' lrrrt'tttlr'., lt(r\\('\('t \\('l(' r('( ()\('tt'tl u't'st ol' lltt' t'e le;tse sttCs.
t73
A
C
,,fi -ffi
EXPERIMENTAL RESEARCH
indicating that they had continued to follow a westward orientation, 
not navigating
northwest to adjust for their southerly displacement as did the adults'
7.2.2 In the laboratorY
No one would argue that ethologists are found studying behavior 
in the field' and I
have suggested that the fleld is the best place for ethological research 
when it is both
feasible and valid. However, much ethological research is also conducted 
in captiv-
ity or the laboratory. Scientists (including ethologists) are not 
judged by where they
work but bY what theY do.
7.2.2t ManiPulation of the animal
Some species can olten be more easily and accurately manipulated 
and observed in
the laboratory than in the fiel<l; proper manipulations contribute to 
valid results'
For example, Buchler (1g76)examined the wandering shrew's 
(Sorex vagrans) use of
echolocation by training six shrews to echolocate the position of a 
platform in order
to <lrop to it. The shrews preferentially ciirected ultrasonic transmissions 
toward the
platform before dropping. when their ears were plugged their ultrasonic 
transmis-
sion rate increased. but their ability to locate the platform decreased 
significantly'
When the ear plugs were replaced with hollow tubes, they located 
the platform as
well as when the ears were not plugged'
The effects of hormones on behavior have been investigated in numerous 
studies'
For example, R.J.F. Smith and Hoar (1961) demonstrated that 
injections of pro-
lactin failed to induce fanning behavior in male sticklebacks 
(Gasterosteus uculeu-
/us), castration reduced the behavior, and injections of testosterone restored 
it'
Estrogen can stimulate nest-material preparation (cutting strips of 
paper) in peach-
faced lovebirds (Agapornis roseicollis) at least two weeks before 
it would normally
occur, but only alter the female is at least 98 days old (orcutt, 1967). 
Lindzey ct ul'
( 1968) measured territorial-markingbehavior in male mongolian 
gerbils ( Merittttt"s
unguic,ulutas) which were either castrated or sham operated 
(contrtll) at 30 clays ol'
age. Marking did not develop in castrates, but when injected with 
tcstostcrorlc tltcy
began to mark earlier and reached higher frequencies than did thc 
cotttrols'
The efl-ects of stimulation of various brain sites on gcncritl bcllitviot'Plttlcttts
(e.g. sitting, standing, eating, crowing) in don-rostic chickctts wct'c sttltlictl 
by votr
Holst and von Saint Paul (1961). f)cthicr itttcl llotlctrstcitt 
(l()'51-i) wctc rthle l()
demonstrate that thc rccurrcnt ncrvc rrrnning l.Rrrtt tltc lot'cgtrt ltt tlte 
lrtltilt si1'ttltls
tlie br.i, tll't6c bl.wlly wlrcrr tlrc rircprrt is tlislerrrlr'tl lrtttl irrltilrrts ltttllrt'r lt't'tltltl'
llycrrttirrgllre rt.(.ur.r.(.llt n(.r\'(. llrt't,rvcrt'lrlrlt'losltou llr:rl lllt'lrl"$ll\ tttllt.ttltttttr'
Itr ir1,t.sI rrrrtrl rl lrrrrrlr lllrl;rlr;r t r'l rtl ( l()l-iS)',lttrltt'tl llr,'r"lt''rl 
lrt'tllt tlt'rt'l"Illl('lll
EXAMPLES OF EXPERIMENTAL MANII'T] LATION
on species-typical behavior patterns. They created domestic chick-quail chrmeras
by transplanting part of the neural epithelium from a quail embryo into the devel-
oping brain of a chick embryo from which the corresponding brain region had been
removed. They found that 'transplants containing the entire quail mesencephalon
and diencephalon resulted in the transfer of certain aspects of species-typical
crowing behavior' (Balaban et al., 1988: I 339).
By studying age- or genotype-dependent behavior in the laboratory, one is essen-
tially making use of natural variation. Fuller (1967:470) focused on genotype elfects
and demonstrated that'albino [house]mice otherwise cogenic with strain C57BLl6J
escaped more slowly from water, were less active in an open field and made more
errors on a black-white discrimination task than their pigmented congeners'. Van
Abeelen (1966), also interested in genetic effects, used 30 behavioral components
performed by individuals and pairs of male house mice to measure differences
between strains DBA|ZJ, C57BL|6J, their Fl hybrids, and homozygous and het-
erozygous short-ear animals.
Dilger (1962) studied the behavior of hybrids between peach-faced lovebirds
(Agapornis roseicollis), which carry nest material under feathers on their backs, and
Fischer's lovebirds (A. personata.fischeri), which carry nest material in their bills.
The hybrids initially tried tucking nest material in their plumage as well as carrying
it in their bills. Even though feather tucking was unsuccessful for these hybrids, it
took two years belore feather tucking diminished to any great extent and carrying in
the bill was almost exclusive (Dilger 1962). This demonstrated the interaction
between genotype and experience.
7.2.2b Manipulation of the environment
Examples of environmental manipulation in the laboratory are widespread in the
cthological literature. As in the field, manipulation of the environment in the labo-
ratory can consist of altering intraspecific factors, interspecific factors, other biotic
lactors and physical-environment variables. For example, providing domestic hens
with expe ricnce in an intraspecific'flock can change the dominant-subordinate rela-
tionships sccn in later paired encounters (King, 1965). Marsden (1968) artificially
irrduccrl changcs in rank in young rhesus monkeys by introducing a 'strange'adult
rrrirlc al ir tirnc whcn the second-ranking female was in estrus or by removing and
re irrIrotlrrcing tlrc currcntly top-ranking female.
N rrrrrcrrrrrs rrntl vru'iotrs irrtcr.spt,t'if ic manipulations have been made in laboratory
('\lx'r'inr('nts. As irn ('xiul)l)lc. Klrlirroski ( 1975) ohscrvccl agonistic behavior between
lr()us(' lirrt lrt's (('ril 1ttt11111 il.\' tttt'\i( ttilu.\) ;ttttl lt0ttsc sl)ill'|1)ws (l\t,tscr dontc,tlit'us)
',rrrrPll' l,\' trt;rtnl;rttrnl' nr\t'rl 1,1()ul)\ rr l:rllot;tl()r v ('iu'('\. Ile systcttllrlicirlly cttn-
Irollr'rl tlr.' ',I('( r("- ,rtt,l '-.'\ ( onrlo',tlto1; ,,', lollotr', ( itrtttp I lirttt Itt:tlt' lttlttsc
EXPERIMENTAL RESEARCH
finches and four male house sparrows; Group II - lour male finches and four female
sparrows; Group III - four female finches and lour male sparrows; Group IV - four
female finches and three f-emale sparrows (one female sparrow died prior to the
experiment).
Turner (1964) investigated social leeding in house sparrows and chaffinches
(Fringilla coelebs) by allowing a caged 'reactor' (either species) to observe simulta-
neously two individually caged 'actors'(both of the same species, either chalfinch or
sparrow), one which was leeding and the other not l-eeding. He found that individu-
als of each species were attracted to feeding and nonfeeding conspecifics. Also,
chalfinches were attracted more by leeding than nonl'eeding sparrows, but this was
not true for sparrows observing chaffinches.
The responses of a caged chalfinch to a stufled owl located at various distances
were measured by Hinde ( 1954). He fbund that at distances closer than l7 f'eet the
chaffinch moved away while at greater distances it moved predominantly towards
the stuffed owl.
As another exarnple of manipulation of interspecific stimuli. Wells and Lehner
( 1978) were able to differentially af tbct the ability of coyotes (Cunis lurruns) to find a
rabbit by manipulating the sensory stimuli available to them. Visual, auditory and
olfactory stimuli were eliminated, respectively, by testing the coyotes in the dark,
with dead rabbits and with an intense masking odor of rabbit feces and urine. Also.
Metzgar (1967) exposed pairs of mice to a screech owl (Ola.s asio) in a laboratory
test area for 2-30 minutes. One was a 'resident moLlse' (had spent several days in the
test area), and the other was a 'transient mouse' (had no prior experience in the
area). The owl captured'transient mice' significantly more frequently.
Potash (1912) measured changes in the abiotic' environnrcn l in his study of the
efl-ects ol environmental noise on separation crowing by Japanese quail ((bturni.r
coturnixjuportica). He lound that ambient noise increased the frequency of separa-
tion crowing and the number of crows per bout, both of which should increase the
detectibility of the signal and the localizability of the sender. Bradbury and
Nottebohm ( 1969) varied the amount of light in a flight chamber ancl measured thc
ability of auditorily impaired and untreated little brown bats (Mwtic luci/irgrt.rl l<t
negotiate a vertical string maze. Dim light and high contrast cnhitrtcccl thc blrts'
ability and was interpreted as evidence that they use pattern vision whilc in llight.
Reynierse (1968) investigated the eff-ect of reliigeration and non-t'cli'igcnrli()r)
during daily maintenance, the intertrial interval. artd the cxpcritttcttlal scssi()n ()n
earthworm locomotion. Hc liruncl tlrut rcl)'igcnrtiorr bclirrc lrrt cx1'rcrirrtcrtlirl scssi()n
art room tenrperatur-c inhihitctl thcir loconrotion. hrrl lrirtl rro cllL'cl il'(lrt'st'ssrr)n \\'ir\
irlstr rtrrt trrttlcr rcl)'ige r':rIirrrr.
Klolrli'r (l()(rl) ttsr.'tl ttutttillttl;tliott ol llrc lttrtltt t'utttt,nttt('nl tt lltt' l;tlr,rt;rlot \ lo
strrrlt' (lrt' rolt' ol t';rtlt r'rl)('rr('n('(' r,rr lr;tlrtl;rl ''r'lr'r ltol1 11, llr,' r lrtllrrltl' ''P,rttotr
FIELD TO LABORATORy: A CONI-t N rrr jM
(Spi:ella posserinrt). He released individuals into a room in which he had placed pine
boughs on one side and oak branches and leaves on the other. He found that wild
caught adults and hand-reared isolated adults prelerred the pine, but that hand-
reared individuals, which had been previously exposed to oak, pref-erred the oak.
Emlen et al' (1976) tested the orienting capabilities of indigo buntings (pu,s.serina
cyaneu) in cages with minimalexposure to visual cues but with an artificial geomag-
netic field provided by Hemlholtz coils surrounding the cage. when the horizontal
component of the magnetic field was deflected clockwise by 120", the orientationof
the buntings shifted accordingly (clockwise to geographic east_southeast).
The effect of different types of feedback (see model, chapter 2) provided by dif-
lerently treated seeds was testecl in black-capped chickadees (puru.s tttric,trpillu.s)by
Alcock (1970)' He presented the birds with striped seeds which were empty, filled
with mealworm to which salt had been added, or contained mealworms treated with
quinine sulphate (an emetic). There was a rapid and stable avoidance of the empty
and ernetic seeds, but they continued to attack the salted mealworms, perhaps
because the food reward outweighed the punishment (salty taste).
7.3 FIELD To LABORAToRY: A CONTIN UUM
Field and laboratory studies Iepresent the extremes along one of the conceptual
dimensions of ethological research (chapter l). However, in practice they comple-
ment each other in a cyclical continuum called a 'research cycle, by Kelly (1967,
1969)' Beck ( 1977)emphasized the value of captive studies in conjunction with field
research' For example, for the six yeiirs following their l3 year field study on vervet
monkeys' Cheney and Seyfarth (1990:ix) 'supplemented [their] research on the
Anrboseli vervets with stu<lies of captive primates'. Likewise, Kummer ( lgg4) con-
ducted a long-term field study and complementary captive research on the social
system of Hanradryas baboo ns ( pupio lrunrudryus).
At the two extremes we have the mensurative (non-manipulative) experiments in
the field and the highly manipulative studies in the laborarory. The middle of the
ctlntinuum is illustratecl by studies conducted in enclosures in the field. For
cxanrple' wecker (1961) set up an instrumented enclosure that was half in an
oitk hickor-y wootllot ancl half in a field, in order to investigate habitat selection in
lrritiric tlcct'ttticc (Pcntrrr.t'scus'rnurticulutus). Wells (1977) used a large outdoor
e ltclosttt'c to itlvcstigitte the relative priority of the coyote's distance senses in preda-li.tl olt l':tbbits. .\t whrr( ptlint cloes the Ileld become the laboratory and vice versa?llintle irn(l Sl)cnccl.-lloolh (19(r7:l(r9), in thcir stucly ol rhcsits monkey behavior,
'tllt'tttPlt'tl l. l('il('ll il (ollll)tirtttist'irr irrr cnt'losurc willr'rr rn.clcratelycomplexenvi-
l()lllll('lll tttttlt't t'ottrltli,tts ttltit lt lx'rnul :r rrrorlr.rlrlt,rlt.p.r.ec.l'cx,ct.il,c,1ltlcantrol
,t ttr I trior lr't trlr.lt pt r.r'r,,t' I r.t r rt 1 1111;, iil
l
,,1
178 EXPERIMENTAL RESEARCH
Hoffman and Ratne r (1973:541) suggested 'that laboratory investigations 
com-
plement and explain the frequently puzzling data obtained in a natural setting'' 
For
example, Cheney and Seyfarth (1990) conducted a l3-year field study of social
interactions, including comlnllnication, in vervet monkeys' In order to test the
hypothesis that vervets recognize members of other groups, they used playbacks 
of
vocalizations (chapter 9) employing the same technique that had been 
used to study
neighbor recognition in songbirds (Brooks an<] Falls, 1975)' Nevertheless' when
interpreting some of their results on vervet'concepts'Cheney and Seyfarth 
(1990:
g4_!5)concluded that'Definitive proof that monkeys are capable of solving social
analogies, and that language training is not a necessary prerequisite, 
can only come
lrom laboratorY tests'.
Ideally, however, research should undergo the fielcl-laboratory cycle 
several
tinres, utilizing to best advantage the important attributes of each. Menzel 
(1969)
considers this process analogous to 'zooming in' and 'zooming out' with a lens'
Avian orientation/migration studies provide a good example' Matthews 
(1951)
lound that homing pigeons released in unfamiliar territory under clear skies 
were
able to fly off directly toward home, but if the sky was overcast they became disori-
ented. That the sun was a clle used in orientatic-rn was given further support 
by
Kramer(|952)whoplaceclstarlingsinacirculalrcagewithsixwindowsgivinga
view of the sky only. The starlings showed migratory restlessness 
(Zugunruhe)' flut-
tering in the proper migratory direction when the sky was clear but in 
random direc-
tions when it was overcast. Kramer altered the apparent position of the sun with
mirrors and was able to reorient the starlings in a predictable manner' Schmidt-
Koenig (1961) kept pigeons under artificial day-night conditions six hours 
out of
phase with the normal day. when the pigeons were released they oriented 90" 
from
the current direction. showing that they were using a biological clock 
atrd the sun's
position as a cue. Kramer trained starlings to find lood in particular trays 
in a circu-
lar cage using only the sun as a cue to direction. when the cage was covered 
and the
starlings were presented with a stationary light, they used the light as if it were the
moving sun ancl changed their direction at the rate of 150/hour. Meyer ( 1964) usetl
instrumental conditioning, discrimination tests in tl-re laboratt>ry to show that
pigeons could indeed detect movement of l5 
'/hour'
Night-migrating warblers (Sytvia atricupillu, s. futrin and s. r'urrrrtttl 
wcrc tcstctl
irr a planetarium by Sauer (1g57)and were shown to use stcllar crtcs 
itt ot'ie Ittltliotl'
Emlen (1967) measuretl the nocturnal orientittion of'cagccl irltligo 
bttttlitlgs ottt-
doors under the natural night sky ancl then took thcnr into tltc 1'rllrrtclltl'ittttt. 
rvlte tt'
they continued to orient thcrnsclvcs ctlrrcclly wltctt tlrc Pllrttctlrt.ittttt 
skv rvrts st'l lot
Iaculc..6ititlns. Tlrcy rcvcrscrl llrcrrsclves w'lre rr llrr'rrotllt sottllt :trts ol lltt'Plltttt'
lttrittttt sky wtts t.('\,(.t.s(.(1.;rrtrl tlrt.v rrr'rt'tlrs,,rit'tttr'tl $lrr'tt llrt'1rl;rll('lillllltll "Lr 
$;r''
rlillrrst.l' rllrrrrrrrrrtt.tl or rl,rrl,r'rrt'tl I rrrlr'rr ( lt,/(l) ,t1",, tt,,',1 ltt'ttttIrtl'tll,ll 
()l 
"l'lt
F IELD TO LABORATORY: A CONTIN t jtlM
pattern movement in a planetarium to demonstrate that the axis of celestial rotzrtion
was important in the development of migratory orientation by young indigo
buntings.
Both field and laboratory studies have provided convincing evidence that geo-
magnetic fields are an orientation cue sometimes used by birds. Moore (l9ll)
showed that nocturnal free-flying passerine migrants responded to natural fluctua-
tions in the earth's magnetic field. Electromagnetic fields produced by large anten-
nas were shown to alter the path of free-flying migrants (Larkin and Sutherland.
1977) and gulls held in an orientation cage (Southern, 1975). Homing pigeons
become disoriented when released under an overcast sky with a bar magnet attached
to their backs (Keeton, l9l4) or with Helmholz coils on their heads (Walcott and
Green, 1914). In carefully controlled laboratory investigations with a cage sur-
rounded by Hehnholz coils. use ol the inclination of the axial direction of the mag-
netic field (increased downward dip as the magnetic north pole is approached) fbr
orientation was demonstrated in the European robin (Erithacus rubet'ulu)
(Wiltschko and Wiltschko 1912) and indigo bunting (Emlen er ul.1976).
The research described above is a very lew examples of the multitude of studies
that have been conducted in the field and laboratory using botlr mensurative experi-
ments and various degrees of manipulation. Literature reviews of species, concepts
and behavior types will generally provide studies representing all approaches from
description in the field to manipuliition in the laboratory. Examples can be lound in
D.E. Davis's (1964) review of the relative contribution of field and laboratory
research to our understanding of aggression and the role of hormones in aggressive
behavior. Above all, astute researchers recognize the value of both description and
experimentation (mensurative and manipulative) and how the various approaches
can be applied in both the field and laboratory best to answer their research ques-
tions (e.g. Holldobler and Wilson 1990).
I see neither halos nor horns on either a real experimentor on accurate
observations. Any method is a special case of human experience, and it
cunnot surpass the limitations of its human interpreters.
IMen:el, 1969:80J
d{-)d-c
C)
r-1*{
f)
o0
?1F{
ofi
{-)()
C)
F(
F{
o
U
lrll-t
B Data collection methods
We are now at the point where: l. the research question has been asked; 2. the sub-
jects chosen; 3. reconnaissance observations made; 4. the objectives formulated; 5. a
descriptive or experimental approach determined, and, if experimental; 6. the
research hypotheses stated; I . the behavioral units to be measured determined; and
8. the experimental design established. Now it is necessary to decide on the proce-
dures to be used to collect the data. You should also select the statistical tests to be
used in the analyses (see Chapters 12-17) belore beginning to collect data.
8.I RESEARCH DESIGN AND DATA COLLECTION
Research design and data collection are mutual dictators. The research design
chosen will dictate the data to be collected; likewise, a knowledge of the type and
amount of data that can be collected will partially dictate the research design to be
used. Research design and data collection are in harness together, and the pushing
and pulling that each does to the other will depend on the individual study and the
experience of the researcher. Experienced observers will use a knowledge of the
animal's behavior and types of data that they can expect to collect to push for the
best research design. On the other hand, neophyte researchers may allow a research
design, selected for statistical attributes, to pull them around in the field, attempting
to collect nearly impossible (and sometimes behaviorally meaningless) data.
Research design and data collection must complement each other lor the study
to be efficient and the results valid. Even seemingly well-planned research can some-
times benefit from redesign and additional (or modified) data collection. Do not be
afraid to evaluate carefully your research design and data collection methods while
you are conducting your study. However, do not redesign your reseorch until you have
curc.filll.t' r/.r.r'r,^r,!(,r/.1,(tur prc.sent antl.future /osses in time, money and clata.
IJ ] Si(.A I,E,S OF MEASUREMENT
I)ltir collcclion involves the assignment of numbers to observations and observa-
lirrrrs to t'rrteg,orics.'l'hrs proccss is rcf'crrecl to as meusuremenl.
,\'r'rllr'r ttf tnt'tt.vttt't)t('ttl al'c lcvcls rll'r'csolttlittn (or itccttracy) of measurement.
Ilrc lr)ur \(;rlr's (Slt'rr'rrs. l()-l(r). r('l)r'('s('nl lloirtls lrlottg ir cotttintttttl ol'rcsoltttion.
I lt;rt t:,. \()nr('lvlx'\ ol rl;rl;r rt'rll rrIIr';u lr' l;rll lrt'l\\'('('n l\\'():ir'itlcs lttttl rtrtry hc rlilli-
( llll ll) t,tlt','ilIl/t'
@5
-..t
-
--
an
o
:
z
?
r,1
-l
'Tl
a
Ell 8g2ll i.,
5'll = 90-tllE:.
ll =5ll !sll sxll -=ll ='.ll :Iilsa
il {.f
ll il
ll :=ili:ll '+ll :kil::ell i x
a lt i=*ilxT
Oq ll -: .-i.(I0 ll =.=a ll i-,.3ll =-'ll3il iil:
il-ll 
=.ll :"ll -ilr
il\il:ll silTil=ill
Ell+lliil
==;?3slulaiEsl_?i ii iii[ i[l EIrAsie=r=7. i a+?= iI qfi.lzdg5'X
=i;gEn=v.;;:14=:AtAifi J:83 
l= ,+ai=i7-i=sEESEiEiAggTil ii *i ll ' !i=7=-do,*2rD:.-= 3_f rIa+*z'ieEArUZz Ir * ll i1=='= ?*v.ii37i;v?'rZzirz i: i ll -3?=; 7+i'1i*:€itl:i3* ?i i llZ=7 ==#,* =i;;ai -E-Fi*r 3 s, + ll=;- zeZ =??Eg?n;Zi;e G= Z ll=- 5= q c"'=2''t'i =Ii+E Ei il- ll=; i. o 'J 6 ? * a 5 5 E 5 6I 
= 
4 f,oo . il'- : G - tr p =_ a = 
i'5 - o ; \ E = 
aH 3, ll ..
z== {E; ig=;:= =a ia a n?, E ll "-\ocotrr 
cc=-
=i=.=='3rDi.;7=. E"== irEE;: arrizi E* ; ll
TaZ ;2 c a;=qoac e A!:!' c., 
= 
ll=' r =-; ii(i'_;i ;;5Ej ;1 I ll
=l- lEi 2i7;?# ;Aar= el p rl!-== ;== 11\q,,=* ;td.tE F;; ll-'_== z=7 ==?*';1 7r=>1 =F E lla T = - c. + .- = - = eP a-':9 =.= :i,?-= ii== SiiEEB ieri; a3 5 il::? =i== E?i?;3 i.-feid ; ll-ooc L''! o
=1,= =1= i.iEi$; e;ii= ? ll;=-? === v,i=-3F 3"iqa+ ll
Dlstance
S- - :: ir..nr rt-ttrdell Score Activitv levei2
Vocal response
Score level3 Score Aggressionlevela
I
2
1
-)
4
5
6
> -1r t. tt
tS u-19.9
Itt -i- 1 7.,
6 t 10..1
_r.7-6. 1
2.2 3.6
1.-3-2.1
o. ,1-l .2
0..1-0.6
0.2-0.3
<0.2
Sleeping
Lying alert
Sitting
Standing
Walking (slow pace)
Walking
(steady pace)
Gentle play
(mouthing. etc.)
Excited pacing
Chase-play (rough-
and-tumble)
None
Few. intermittent
Few, close
Many, intermittent
Many, close
Full or continuous
0
1
2
-)
4
5
Intruder antennated (as in 2), but if
mobile. is not followed. if intruder is
stationary, resident ant does not stop
Intruder antennated for less than 2 s: if
mobile, intruder is lollowed slowly for
severalcm; if intruder is stationary,
resident stops
Rapid antennation of intruder, antennae
extended lor greater than 2 s
Mandible gaping, rapid antennation;
'sidling' (maintaining a lateral orientation
to and slowly circling intruder)
Alarm (running, abdomen elevation and
vibration) and recruitment
Intruder'held'. but released; biting; no
abdomen-curling
Intruder'held'(as in 8), but released,
abdomen-curling ( stinging posture)
by residents, but no stinging;biting
Intruder surrounded and 'held'in
mandibles by petiole and appendages;
appendages pulled bitten off, eventual
stinging
Lnmediate lunge. grab and stinging
.\-olss.'
1 '' From Studd and Robertson ( 1985).
I From Bekoff and Corcoran(1975).
I Examples lor ants, from Obin and Vander Meer (1988).
Sourc'e: Copyrighted by Bailliere Tindall.
DATA COLLECTION METHODS
scored level of aggression during feeding bouts in Siberian lays (Perisoreus inJhus-
/as) on a scale of 0 to 3; Studd and Robertson (1985) used a scale of 0 to 5 to score
movement of yellow warblers; Riechert (1984) scored agonistic encounters in
spiders on a scale of I to 35. Note that the number of intervals in the examples in
Table 8.2vary from 6 to 9.
These have all been examples of using an ordinal scale on the dependent vari-
able (behavror units), but ordinal scales can also be used to rank values of the inde-
pendent variable. For example, Moller (1987) used an ordinal scale of I to 5 to
rank the variation in badge size (amount of black coloration on the breast and
throat) in house sparrows; Rohwer (1977) used 14 intervals to rank badge size
('studliness'categories) in Harris'sparrows (Figure 1'1)' Alatalo et ul' (1990)' in
their study of female preference, ranked the percentage of brown and/or grey
feathers on the backs of male pied flycatchers (Ficedula hypoleuca) using an
ordinal scale of I to 7. Ward (1983) measured sexual dichromatism in 24 fish
species using a four-point ordinal scale of skin color on three areas: the head. and
the dorsal and ventral surfaces; the sum of the three ranks was used as the
measure of sexual dichromatism. Another example of an ordinal scale of mea-
surement for an independent variable is the Beaufort Scale of wind velocity mea-
surement described in ChaPter 4.
Measurements (scores) based on an ordinal scale are sometimes weighted to
reflect relative differences in the intensity of behaviors, and they are occasionally
combined with other measurements to create a compttsite score' Example of both of
these are provided by Lightbody and Weatherhead's (1987) study of lemale choice
versus male competition in yellow-headed blackbirds (Xunthocephalus xantfio-
cephulu,s)(Table 8.3); note that the ranks jump lrom 6 to 8, then to l0 and l3' In
addition, the ranks were multiplied by the durations of the male's behavior and then
summed lor a comPosite score'
Also, all the behaviors do not have to have different scores. [f several behaviors
reflect the same intensity, they can be assigned the same rank' As an example'
Cigliano (1993) studied dominance and den use in Octopus bimugulatus by record-
ing the occurrence of eight attack and withdrawl behaviors. These behaviors were
weighted on an 'intensity of response scale'of 0 to 4, but four of the attack behav-
iors were all given the score of 2. Likewise, Barki et ul. (1992) deterrrlinecl the ell-cct
of size and morphotype on dominance in prawns (Mat'rttbrttt'hittttt