The most straightforward means to derive natural history information is direct observation. Its value should not be underestimated, as direct observation is often the most effective way to place the trait in context of the animal's physical and social environment. The observer might be able to learn more about a species from a few hours of direct observation, than from a year of examining trip-camera photos or radio telemetry locations.
When designing a direct observation study, all terms must be understood and quantified, especially when more then one observer is used. The term "feeding" is readily understood at a basic level, but there are often many types and gradations of feeding in a natural setting. As with village interviews used to create a species list, the attitude and background of the observer sometimes influences how a behavior is recorded. An observer has to guard against anthropomorphic biases and also against interpreting events through preconceived theories. For example, which animal is considered dominant during an interaction should not be a qualitative measure, but based on quantifiable criteria.
As with indexes, direct observations often have a unit of effort. How many attempted matings, bark strippings, or so-
cial grooming events observed is always a function of how much time was spent observing the animal. This is complicated when animals are part of a social group. Time spent monitoring the entire group is not the same as time spent observing one individual in the group. Usually too many activities are being conducted simultaneously to watch an entire group and researchers identify focal individuals that are monitored for a set period of time. This set period of individual observation might be punctuated by a sample of the behavior of each group member, referred to as a scan sample.
Direct observations are usually inexpensive; a good pair of binoculars or spotting scope and a watch are the main expenses. However, time is usually the limiting factor with direct observations. Many hours can be spent to obtain a few minutes of direct observation. With more cryptic or more diffuse animals, there is a point at which the observations are not worth the time spent to obtain them. Video cameras and recording equipment can be used to continuously monitor a location, with the tapes reviewed by the researcher at a later date; but
this would only be effective at feeding or watering sites that attract animals. In addition to time considerations, there is also the issue of how the observer's presence impacts the animal's behavior and movements. If the behavior being recorded is the result of the animal's movements away from the observer, or toward a concentrated food site, then the value of the observation is reduced. A period of habituation of an individual or group to the observer is standard practice. But this needs to be considered with some care. For instance, too much familiarity can trigger attacks, or habituated animals may be vulnerable after the study is terminated.
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