Song development in the grasshopper sparrow, Ammodramus savannarum

Please cite this article in press as: Jill A. Soha (2009), doi:10.1016/j.anbehav.2009.02.021 T E D P R O Adult male grasshopper sparrows sing two structurally and functionally distinct songs: buzz song and warble song. To investigate how these songs develop, we tutored three groups of young males in the laboratory: one with recordings, one with live adult tutors and one with no song (isolate birds). We used visual scoring of spectrograms, principal components analysis of acoustic measures and spectrogram cross-correlation to analyse the results. Tape-tutored and live-tutored birds developed structurally normal buzz songs and largely normal warble songs. Isolate birds developed moderately normal buzz songs along with one or two more atypical songs. Neither buzz songs nor warble songs were accurately imitated by any of the tape-tutored birds. Live-tutored birds imitated buzz songs, but not warble songs, more closely than did tape-tutored birds. We also examined buzz songs in a population of grasshopper sparrows in the field. Comparisons of buzz songs of yearling males with those of their social fathers and with those of their first-breeding-year territorial neighbours indicate that sons do not imitate songs of their social fathers, and imitate songs of their immediate territorial neighbours only to a limited degree. Overall our results suggest that grasshopper sparrow song does not develop by imitation but that exposure to conspecific song is important for normal song development. Differences in development of the two song types may relate to both acoustic structure and function of these songs. 2009 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.