Bird song is widely recognized as a model system for investigation into the biological basis of learning. Its status derives from the many striking parallels between song communication and human language and the recent discoveries concerning brain mechanisms underlying song learning. Indeed, bird song has become the major vertebrate model for the study of the neurobiology of learning. Dr. Beecher will use both field and laboratory studies to examine song learning in one representative species, the song sparrow. The field perspective is crucial for understanding the song learning process, because the "rules" of song learning that Dr. Beecher has discovered in the field turn out to be quite different from the rules that had been inferred from laboratory studies. Dr. Beecher will try to resolve this discrepancy through a combination of laboratory and field studies. Resolution of the discrepancy is crucial to the effective use of bird song as a model system, for we cannot hope to work out the neurobiology of song learning if our understanding of song learning is incomplete or incorrect to begin with. In the laboratory, Dr. Beecher will directly test hypotheses concerning song learning derived from his long-term field study. The key point is that each of these hypotheses is either not indicated or actually contra-indicated by laboratory studies to date. (1) The young bird copies whole songs of particular older individuals or "tutors" (he develops no cross- tutor hybrid songs). (2) He learns some songs from all tutors to whom he is exposed. (3) If two or more tutors sing different versions of the same song type, the young bird combines these. (4) Types shared by two or more tutors are preferentially learned. (5) The critical period for song learning extends well beyond the "classical" period identified in laboratory studies. Dr. Beecher will try to validate these conclusions by laboratory experiments in which he simulates the essential conditions that occur in the field (including: the bird hears live tutors, not tapes, he is exposed to the tutors sequentially during the critical period, and he can socially interact with his tutors). Dr. Beecher also will continue laboratory experiments on song perception, with a particular view to relating these results to the increasing body of knowledge concerning the function of song centers in the brain. Finally, he will carry out further field studies on the natural context of song learning.
