BEHAVIOR FIELD LABORATORY, ECOL. 4960/5960 (DAVE GORI)
INTRODUCTION TO BEHAVIORAL ECOLOGY: QUANTIFYING BEHAVIOR USING TIME BUDGETS
AND FOCAL ANIMAL OBSERVATIONS.
Behavioral ecology is the study of how an organism’s environment, the physical environment,
social and biological environment, shapes its behavior through the action of natural selection,
kin selection, and sexual selection. [Kin selection is a special case of natural selection
involving related individuals and the selection of genes that individuals share with their
relatives through common descent. This form of selection is responsible for the evolution of
altruistic behaviors where individual fitness is reduced by performing the behavior but close
relatives benefit disproportionately.] Like morphological characteristics (i.e. finch beaks),
behavior is tremendously variable between individuals in form and frequency. Ultimately,
behavioral ecologists are interested in how this variability affects an individual’s survivorship
and mating success as a way of understanding the evolution of behavior(s).
The objectives of this lab are to: 1) observe the behavior of a selected species and be able to
identify/describe a series of its behaviors; (2) learn how to do a time budget on focal
individuals to quantify the amount and frequency of different behaviors; (3) use your time
budget observations to generate 5 questions about a selected behavior(s); and (4) take one of
these questions and design a study to answer it.
To do this, you will first select a study species for this excercise. Some possible choices
include: Galapagos sea lions, marine iguanas, foraging finches, reef fish or lava lizards at
Loberia. Once you have done this, watch an individual or if possible several individuals for
approximately ½ hour, identifying and describing as many behaviors that you possibly can.
These may include calls, displays, movements made during food searching, interactions
between individuals, etc. In this identification phase, clear your mind, open your eyes…..look
and see. Ask yourself the following questions for each behavior that you identify:
Who is performing this behavior (sex, age, individual) and who is it directed to?
When was the behavior performed, e.g., time of day, after feeding or mating, and roughly how
frequently was it performed relative to other behaviors?
What context is the behavior performed in (e.g. a fight between two males over food, a chase
between females that arose when female A approached B) and what might determine the
frequency and intensity of the behavior if this varies between individuals and for a single
individual over time?
Why? This is the type of question that deals with how the behavior evolved and involves
speculating about the advantage of the behavior in terms of increased survivorship, mating
success and offspring production by the individual/performer.
After you have described a series of behaviors and have asked yourselves these questions
(N.B., you don’t have to have answers to any of them in order to proceed), pick a focal animal
and perform a time budget on that animal for ½ hour. You’ll need a watch with a second
hand or display for this. The time budget involves marking the time when a change in
behavior occurs. For example, when you start the time budget (time 00) a male bird is calling
from a perch; you can keep track of the number of calls by making hatch marks on your time
budget sheet. 2:50 minutes into the observation, another male flies up (his neighbor on the
left); the focal male displays, stretching his neck over his left shoulder and does this 5 times,
continuing to call. At 4:37 the male flies off the territory to forage, and returns at 9.05,
perches and calls. At 12:22 a non-neighboring male flies up and your focal male continues
perching and calling.
You might record the following sequence of events on your time budget sheet as follows:
00
P, C ////////////
2:50 N on left → NS, NS, NS, NS, NS ///////////////////////////////////////////
4:37 off T, F
9:05 Returns, P, C ////////////
12:22 NN arr., P, C //
From your exploratory observation, you’ve already identified P, C, NS, N, NN, off T and F as
perching, calling, neck-stretch display, neighboring male, non-neighboring male, flies off
territory and foraging, respectively. Be sure to make an abbreviation key so that when you
analyze your data later, you’ll be able to decipher your time budget. Also, provide
information at the top of the sheet about who the focal animal is, the time when the budget
was initiated, and general notes on weather conditions which can have strong effects on
behavior. In a population of banded birds, it is relatively straightforward to identify an
individual. If individuals are not marked, you can identify sex, age, size, plumage
characteristics, unique markings or any number of descriptors that will enable you to
categorize and later distinguish the time budget of one individual or category of individuals
from that of another. For territorial individuals you can produce a quick map showing the
location of the focal animal relative to neighbors.
Since more data is always better than less in research, if behaviors are not coming fast and
furiously, try watching 2 or more individuals during a single time budget. This will probably
not be possible if you’re watching foraging finches or sea lions at dusk but will be possible if
you’re watching a group of marine iguanas. If behavior is changing to fast to keep up with for
a single individual, try breaking each minute into 10 or 15 second segments and at each 10 or
15 second break , record the behavior that is occurring precisely at that time break.
After completing your first time budget, switch to another focal animal(s) and perform
another time budget (½ hour).
To summarize the time budgets for analysis, you can calculate the amount (percent) of time
that the focal animal spent doing each identified behavior and the frequency or rate of a
behavior per unit time (e.g., percent of time a male spent on territory, number of calls per
minute on territory, etc.)
Once completed, reflect on your exploratory observations and two time budgets and then run
through the who, when, what, and why questions, generating 5 of your own questions
regarding behavior(s) that you’ve just observed. Pick one of these questions and design a
simple study to answer it, perhaps using time budgets to do this. If needed, Katrina and I will
help you with this step.