The Fieldwork of Ethology The early students of ethology were often called "bird-watchers" because they began their work by observing the behavior of birds. Fieldwork involves repeated observations of a subject over long periods of time. Eventually, a sequence of behavior emerges, and then it is possible to read the language of the behavior. For example, Lorenz observed that the courtship sequence of the mallard duck involved some ten segmented parts, such as bill-shake, head-flick, tail-shake, and gruntwhistle. In certain instances, fieldwork with insects and lower animals offers the possibility of direct experimentation. In his attempt to translate the dancing motion of bees, von Frisch made the food source available. Consequently, he was able to vary the distance of the food source, change its location, and alter the quantity of food. Each change in the variables produced some variation in the dance-perhaps a new "phrase" added to the language. In other areas of research, the test subject can be modified for direct experimentation. When William Keeton attempted to explain how pigeons found their way home, he used contact lenses to cover the eyes of the pigeon to block out the position of the sun. He also created secondary magnetic fields around the pigeon to test the subject's sensitivity to the earth's magnetic field. While all studies of stereotyped behavior begin with observation, either in the field or in controlled settings, further exploration usually requires laboratory research. In Jack Hailman's study of the learning component of sea gull chicks, he constructed models of gull parents and correlated pecking accuracy with growth. He also modified features of the model sea gull to study possible changes in responses from the chicks. As the search for the causes of instinctive behavior moves further into the organism, the methodology follows-into areas of brain function (neuroethology), the chemistry of innate behavior, and the genetic component of behavior. Investigating the source of egg-laying behavior of a species of a large marine snail (Aplysia), Richard Scheller and Richard Axel found three genes that produce a number of peptides that govern this behavior.
Wolf Packs Wolves are one of the best-known examples of animals that form packs for cooperative hunting and rearing of cubs. Most packs consist of fewer than eight members, although two or more packs can temporarily come together. When this happens, a pack may accept one member of another pack, while rejecting and chasing other members away. The packs always include a breeding pair of adults, some pups, subadults, and other adults, some of which may be allowed to breed in addition to the dominant pair. Packs can produce up to six cubs per year, and more than one female can reproduce, but often the dominant female will interfere with the care of the subdominant female's cubs. Wolves prey on deer, moose, buffalo, sheep, caribou, and elk. The stimulus for beginning a hunt is apparently the completion of consumption of a previous kill. Wolves typically pursue prey by direct tracking, although they can occasionally come upon prey by chance encounter. Once they have located their prey, which usually occur in herds (except moose), they begin stalking until they get within feet of their targets. They then rush the target and chase it. Chases can last for less than a mile or for long distances over several days. They focus on the weakest targets: young, old, and sick prey. The wolves can injure a prey animal and then leave it alone for several days, resuming harassment until the prey can no longer rise and run. The pack then attacks from all sides to kill. Wolves have been described as hunting in an extremely cooperative manner. However, what is more generally observed is that wolves in a pack attack the rear quarters of their prey, and the weight of many wolves biting and slashing on this area helps to bring the prey down.Wolves apparently have a low hunting success rate, which means that they must hunt frequently and test many individuals within a herd before finding one that displays some characteristic likely to be disadvantageous. While many have postulated that wolves form packs to facilitate food capture and that an increase in the pack size will help to increase the amount of food captured per individual, there is, in fact, a negative relationship between pack size and food available per wolf. Packing behavior may instead be more dependent on cooperation between kin where adults can more efficiently share their food with offspring, and young can obtain more food by remaining with their parents than they could by hunting on their own.
