Introduction to Ethology Part 2: Quantifying Behavior
Bio 112 Lab, Spring 2016
Describing Action Patterns
In order to study and measure behavior you must break the behavior up into units, called action patterns. These become evident to you when you watch an animal. As you become familiar with its behavior, you immediately see that its behavior is not continuous. Instead, the animal performs discrete, repeatable acts that you can identify. These discrete, repeated acts or bodily postures are what we call action patterns.
Action Patterns, then are:
• discrete, complex muscular movements involving many muscular contractions that are closely associated temporally
• repeated in essentially the same manner time after time (i.e. they are stereotyped) and
• they are similar among individuals of the same species (i.e. they are species-typical).
Action patterns are often defined in terms of the following characteristics:
• the form of the action.
• the velocity of the action — how rapid are the movements of the action pattern?
• the duration or how long the movements are held in different positions.
• the amplitude or the height of the action.
• the orientation of the behavior towards objects in the environment, including conspecifics.
Look at the action patterns for mallard ducks depicted below. One is a posture (head-round) while the others all involve motions from simple head shaking to more complex motions that involve much of the body:
Major Approaches to Quantifying Behavior: Survey vs. Focal
Once you have completed your catalog of behaviors, you are ready to quantify how your animal spends its time. There are two main methods to do this:
Survey approach: Watch many individuals at the same time. At systematic (or randomized) times, you count the number of individuals performing each possible behavior that you previously cataloged. For example, if you are watching a flock of ten geese in a lake, you might set your timer to alert you at one minute intervals. When the timer goes off, you note what each of the geese in the flock are doing at that instant, as well as the context and consequences of their actions. You will repeat this every minute for your entire observation period. Taking survey data in the field also is facilitated by creating a data form that can be filled in quickly. We are less likely to use the survey method in this course, but it can be used if necessary.
Focal approach: Locate a single individual and follow its behavior for a standard time (or as long as possible up to that time). If a focal individual moves out of your view, then you start a new sequence of observations on a new focal individual. Selecting the focal animal can be systematic (e.g. only watch males) or randomized (select a random number from a table, then follow the nth individual encountered). During a focal study, you should record the following data as they occur:
- the context (date, time, location, weather, habitat, social context)
- the focal animal ID (if you can identify them uniquely, or just by #1, #2, etc)
- the sequence of behaviors
- the duration of behaviors (using a stopwatch)
- the immediate consequences (e.g. responses of other individuals, etc.)
You won’t have time to take extensive notes during focal observations. Your catalog of behaviors (action patterns) must be used to make organized data sheets that allow you to record data quickly and efficiently during the observation period, and to tabulate the results accurately afterward. A well-written catalog of behaviors will allow the creation of a form for collecting data for the quantification phase of the ethogram.
Summarizing behavior: Transition matrices, kinematic diagrams, & time budgets
Sequences of Behavior. Behaviors often do not occur in isolation and so we quickly want to move beyond a catalog of behavior. Thus, once you have the have the action patterns clearly defined and the catalog written down then you can begin to record sequence data during focal observations. The ultimate goal will be to produce a diagram that summarizes the likelihood of various behavioral sequences. This type of diagram is called a kinematic diagram. To understand its usefulness, we’ll go through the steps of creating one and then see what it will tell us.
Let’s assume that we are observing mallard ducks and we are interested in situations where the following behaviors are common (some of these were shown above):
bd bill dip
hs head shake
pw preen wing
tw tail wag
wf wing flap
bs bill shake
**Note that a short, easy-to-remember abbreviation is given for each action pattern. This makes recording data easier.
Now, suppose that you are watching a duck. You simply record the action patterns in the order in which they occur, i.e. the sequence of events. The following is an example of a possible sequence using duck action patterns:
(Begin) bd hs pw bd hs pw bd hs hs bd pw bd hs pw hs hs hs pw bd hs
pw bd hs wf tw bd hs pw bd hs hs pw bd hs hs pw hs wf tw bd (end)
**Note that three head-shakes in a row are recorded as “hs hs hs,” not just as “hs.” We can use the observed sequence of action patterns to construct a matrix that lists the number of times that each behavior follows another. Thus, it gives the number of times that there is a transition from one type of behavior to another.
This primary transition matrixhas in its left-most column the codes for all the action patterns that were observed (the blue lettered codes in the example below). These same abbreviations are also used as headings for each column in the top row (in red below). Each cell will contain the number of times the behavior indicated at the left (in blue) was followed by the behavior heading the column (in red). To obtain these counts, you start with the first two observed action
patterns (bd followed by hs above) and score it. You then shift along by one behavior (so the next sequence is hs followed by pw then pw followed by bd, etc). The result is a matrix that shows the number of times each behavior listed in the column on the left is followed by each other behavior. Thus, it gives the number of times there was a transition from one type of behavior to another. As was noted in the box above, a behavior can repeat itself — follow itself.
The total number of times a sequence starts with a particular action pattern is given in the right-most column (purple).
Here is the matrix that shows the number of each type of transition for the sequence given above:
**Note that in the sequence bill shake “bs” did not occur and so it is not in the matrix.
We next calculate the transition frequency for each behavioral sequence. This is simply the percentage of times that a particular action pattern follows another (given the first action pattern). For example, since 9 out of 10 bd were followed by hs, the transition probability is 9/10 = 0.9.
Here is a transition frequency matrix based on the data on the previous table.
**Note that transition frequencies as read across a row must sum to approximately 1.0 since that is all the action patterns that followed a particular behavior. On the other hand, there is no reason that individual columns need to add to 1.0 since each only contains the proportion of times an action pattern was preceded by a particular AP.
The matrix shown above was constructed from a single sequence of action patterns, such as would be produced by one continuous observational session on an individual animal. Usually, however, a matrix is constructed from a set of sequences from individual animals. Sometimes, separate sequences may also be recorded for the same individual if continuous observations of that individual are periodically interrupted (e.g. if the animal flies away and returns later).
Kinematic Diagram: A kinematic diagram simply shows the flow of the behavior. Making one is like constructing a puzzle. First, place the abbreviations for the action patterns in boxes. You may want to add sample sizes (from the primary transition matrix, right column) into the box with each behavior. Next , start with any behavior and draw arrows to the boxes containing the
other behaviors that occur after it.
Here is an example starting with bill dip which was followed 10% of the time by preen wing and 90% of the time by head shake.
Notice from the transition frequency matrix that bd follows tw but not the reverse order. The direction of the arrows indicates which behavior leads and which follows.
We then add other data from the matrix. First, we add transitions from head shake.
Notice that 6.25% of head shakes preceded bill dips etc. Also
notice that head shakes sometimes followed other head shakes. That is what the arrow that starts and finishes on head shake indicates. (I have removed the total number of observations from this and the remainder of the diagrams so as to keep things simple.)
Next we add the transitions for preen wing (in blue):
…and finally we add the missing behavior, tail wag and its transitions:
Now, this is hard to read with all its crossing lines, so let’s re-organize it a bit while preserving all the data.
There are a number of ways to do it, but here is one version of a result:
How do we read this table — what is the use of a kinematic diagram?
Notice that at a glance you can see which action patterns follow which others and the frequency with which various patterns follow follow each other. By examining transitions over different individuals or in different conditions, you may learn about “complexes” of coordinated behaviors. Also, you can ask questions about how different conditions influence the flow of behaviors through time. This can help you to form questions and hypotheses about the behaviors.
Time Budgets: An ethogram gave us a list of the characteristic action patterns of an animal and the kinematic diagram gives an excellent overview of behavioral sequences and how frequently certain behaviors occur. However, neither really tells us how much time an animal spends performing each behavior. Note that even though a behavior is very common, it may be that the animal still spends very little time at it because it is brief. Time is an important commodity to all organisms, given that life is finite and that opportunities are often fleeting. Time can also be a good stand-in for energy — especially if the activitiy is steadily performed.
A time budget for an animal is just like one for a human — it lists the percentage of time that an animal spends doing various activiites. These “activities” may be either particular action patterns such as producing a territory call or they could be more broadly defined activities such as territory maintenance. The latter would include calling, patrolling and perhaps even
fighting.
Time budgets are obtained by:
• defining the behavioral units under consideration (somewhat and perhaps totally akin to obtaining an enthogram)
• measuring the time spent on each of these
• totalling the time
• obtaining a fraction for each activity.
To construct a time budget, you must add the time spent on each behavior for each individual. Then calculate the proportion of time spent on particular behaviors, out of the total observation time. When you are able to observe several different individuals, then each individual can be a “replicate” or independent estimate of time allocation to the behavior of interest. You summarize your data by doing a time budget for each individual, then calculating mean values for each behavioral measure of interest.
Time budgets are very important in behavioral (and physiological) ecology. For instance, it can be useful to determine how much time male crickets spend searching for mates, resting, building burrows, feeding, and calling. Note that most of these activities are more complex than typical action patterns — perhaps only calling (a very stereotyped behavior involving raising the forewings 45 deg. and then stridulating them against each other many times each second) and resting would be considered an action pattern. The others are complex patterns involving many
specific action patterns. Time budgets can be used to work out a respiratory energy budget . These tell how much energy a cricket expended in various activities. In one species, Anurogryllus arboreus, males use about 25% of their daily total energy expenditure calling to
females. They do this in about 25 minutes (i.e., less than 2% of the day)!
Introduction to Ethology Part 2
PRELAB ASSIGNMENT: Print and turn in this ONE page for the pre-lab
Use the following mock-data to construct a primary transition matrix, transition frequency matrix, and kinematic diagram of the mock cricket behavior. Then provide a 1-2 sentence description of the ethogram.
Catalog of male cricket behaviors:
ch = chirp (makes repeated sound with wings ~5 sec)
pa = preen antenna (contacts antenna with palps)
pl= preen legs (contacts legs with palps)
st = still for 10-20 sec. (stationary, no interactions or chirping)
ma = male approach (approached by male)
mc = male contact (contact with male)
fa = female approach (approached by female)
fc = female contact (contact with female)
di = displaced (moved out of previous position by another cricket)
mt = mating (copulation with female)
Mock Data (a very brief focal study):
st st st ch st ch ch ch st st ch ch ma st st ch ch st ch ch ch fa ch ch st st ch ch ch ma mc di
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