Nowicki & Searcy, IBN 9408360, Perception, Function and Development of Complex Vocal Signals Animal communication plays an important role in many biologically critical arenas, particularly social behavior, including territorial defense and the attraction and choice of a mate. Bird song is one of the most spectacular cases on this type of behavior, and much of what has been learned about the development and evolution of animal communication has been the result of studies of bird song. In this research project, Dr. Searcy will investigate several aspects of a common characteristic of bird song, different song types. In many songbirds, the males sing variable songs which can be classified into a small number of song types. For example, male song sparrows sing five to thirteen different song types each. This pattern is found in many species but little is known about either how such variability in song develops in the individual or about how it functions in an evolutionary sense. A series of experiments conducted in both the laboratory and the field will investigate: (1) the abilities of song sparrows to discriminate variation both within and between song types; (2) the ways in which such variation contributes toward either attracting a mate or discouraging other territorial males: (3) the extent to which song sparrows differ in the amount of variability in their songs in different regions of the country; and (4) the role of learning and cultural transmission in the development of song type variability. Taken together, the results of these studies will advance the understanding of the evolution and development of animal communication.
