A Review of Some Aspects of Avian Field Ethology

T•E last 30 years have seen the development of a new approach to the study of behavior, which has increasingly interested ornithologists as they have attempted to understand avian biology fully. This new approach is now known as ethology. Both amateur and professional ornithologists have contributed to its progress from the beginning. A basic tenet of ethology is that all behavior of animals can eventually be understood. The ethologist attempts to explain behavior functionally (what does it do for the animal?), causally (what are the internal and external factors responsible for each given behavior?), and evolutionarily (what is the probable phylogeny of the behavior, how does it contribute to th'e survival of the species, and what are the selective pressures acting upon it?) (see Tinbergen, 1951, 1959; Hinde, 1959b). Some basic procedures are essential in an ethological study (Hinde, 1959b: 564). The first step is to describe and classify all the behavior of an animal, at the same time, if possible, dividing the behavior into logical units which can be dealt with further in other disciplines--particularly physiology and ecology (see Russell et al., 1954). Although studies often begin qualitatively, they eventually should be quantified. Generalizations, which are to be valid for many species, must be based on work using closely related species first, and more distantly related ones later. The animal is studied as an integrated whole. Some workers, notably Konrad Lorenz, keep and breed animals in captivity under close scrutiny. Most of this paper deals with communication of birds. We have stressed particularly the analysis of displays, their evolution, and their relation to taxonomy--topics of great interest to systematic ornithologists as well as to ethologists. In addition, we discuss certain maintenance activities.