Jenna Kitchings
Alicia Pearce
Amanda Smith
Behavioral Ecology Sp2009
3-10-09
Ethogram Methods Comparison: Behavioral Continuous Sampling, One-Zero Sampling, and Scan
Sampling
Abstract
Introduction
Animal behaviors can be observed and acquired using several methodologies, ranging from one
zero scan to behavioral. These methods can be used to compile an ethogram for groups in a population.
Behavioral sampling is continuous and in real time, and allows the observer to gather accurate ratios for
behavior composition during viewing time. Scan sampling in this instance involves only the first second
of every minute observed for the number of cows being watched. One Zero sampling uses each minute
as an interval and records whether a behavior was observed in that interval, but only once. It is also
known as the Hansen Frequency Method (Leger, 387) or “fixed interval time span sampling” (Bateson,
54). Each presents its own advantage and disadvantage (limitations) to compilation of behaviors in a
population. One zero sampling has been known to create issues with both too short an interval time
and too long. Multiple bouts of the same activity can be missed in the same interval with one recording
with an interval too long, while the same bout of activity can be counted more than once with an
interval too short (Leger, 392). A positive aspect to one zero is that if the interval is chosen correctly,
the data can accurately estimate behavior rates, measuring time utilization (Leger, 387). Interval should
be based on the overall activity rate of the species being observed so that slower animals have the
longer interval times (Gygax, 139). The data recorded should be accurate, repeatable, and relevant to
the behavioral group.
Methods
Behavior
Behavioral sampling was used to observe three individual cows for ten minutes each. The
behaviors of the individuals were continuously recorded for the ten minute period. This method was
used to observe rare behaviors that tend to be missed by other methods of sampling (Bateson, 51).
Scan
Methods for the scan sampling consisted of just one recording for the start of each minute.
Each of the fifteen cows (three at a time) were watched for ten minutes and at the first second of each
minute the behavior for that second was recorded. Therefore, each cow’s behavior was only being
observed for ten seconds out of an hour.
One Zero
In One-Zero Sampling, cows were recorded as to the activity they were performing for each of
ten intervals during the ten minute time period in which all three sampling methods were being used by
three separate people. This was repeated for three cows at a time for five ten minute intervals,
comprising a total of fifteen cows. During each one minute interval, cows were recorded as to whether
the activity was performed in that interval, and each activity was recorded only once per every minute
interval.
For each set of sampling data, any action performed so that N<3 was removed. All ten minutes worth of
data gathered was gathered simultaneously for all three sampling methods, along with the same focal
individuals.
Results
Figure 1 shows the categorical data obtained for scan sampling. Figure 2 is data for One Zero sampling,
and Figure 3 shows categorical rates from behavioral sampling.
Relative Rate (Number of times
behavior performed/number of times
recorded)
1
Figure 1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
eat
motionless
other
walk
Relative Rate (# of Intervals
Performed/# of Intervals
Cow Behavior
1
0.8
0.6
0.4
0.2
0
Cow Behaviors
Figure 2
Figure 3
1
0.9
Rate (Behavior/mn)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Cow Behaviors
Discussion
Since three of the individuals were scanned rapidly at regular intervals, the researcher is
restricted in that the behavior between each minute is not observed; therefore you are unlikely to see
the individual doing every behavior. Therefore, scan sampling in this instant was not necessarily the
most useful. Instances were scan sampling would be the best method could be when you are collecting
a large amount of data on a group of animals were the behaviors are very easily identified. Behavioral
sampling is good in that the observer can view rare or normally unnoticed behaviors that other sampling
may miss. The data is also in real time and gathers an accurate rate instead of a relative rate. But since
continuous behavioral sampling requires the observer to watch three individuals at one time, some
behaviors may be missed or may go unnoticed. Overall, there would be a higher percent error. Data
concerning One-Zero sampling is skewed in the fact that the longer each interval is, the less accurate the
data will become since each action is only recorded once. However, previous research indicated that for
data concerning cows, an interval as long as 2, 8, and even 17 minutes is possible for accuracy (Gygax,
139). For this reason, data is similar between scan and one zero sampling, and is only differed in ratio to
behavioral sampling in the walking action recorded. The concordance of information shows that a one
minute interval is appropriate in dairy cows to gather an accurate relative time management scheme of
activities using one zero sampling.
References
Bateson, Patrick, Martin, Paul, 2007. Recording Methods. Ln: Griffiths, Martin. Measuring Behavior: An
Introductory Guide. 3rd edition. United Kingdom: Cambridge University Press. p. 48-61.
Gygax, Lorenz, Neison, Geisam, Wechsler, Beat. 2009. Choice of san-sampling intervals- An example
with quantifying neighbors in dairy cows. Applied Animal Behavior Science. 116: 134-140.
Leger, Daniel. 1977. An Empirical Evaluation of Instantaneous and One-Zero Sampling of Chimpanzee
Behavior. Primates. 18(2): 387-393.