My research addresses the interface of animal behavior, organismal biology, and evolutionary biology. I am particularly interested in a question first articulated by the ethologist Niko Tinbergen: How do proximate mechanisms of behavior, such as biomechanics, physiological performance, and development, shape the evolutionary diversification of behavior? My work focuses on vocal behavior and evolution in vertebrates, especially songbirds. Laboratory work aims to characterize the influences of acoustic experience and production mechanics on vocal expression in songbirds. Experimental studies of vocal learning in hand-reared sparrows are used to assess how limits on vocal proficiency constrain the evolution of vocal frequency, timing, and syntax features. Complementary laboratory activities include quantitative surveys of vocal diversity using bioacoustic analyses, characterization of vocal motor patterns through high-speed video analyses, and experimental manipulation of vocal tract function. Many of these studies are conducted in collaboration with Stephen Nowicki and Susan Peters of Duke University. Field work is conducted in the eastern United States, Brazil, and the Galápagos Islands. Local field studies address questions of song function and perception in birds. Studies in Brazil, conducted largely in collaboration with researchers from Brazilís Instituto Nacional de Pesquisas da Amazônia, aim to document vocal behavior in poorly-known vertebrate taxa including river dolphins, arboreal rats, and poison-dart frogs. Work in the Galápagos asks how, in Darwinís finches, the evolutionary diversification of vocal tract morphology has shaped the evolution of vocal proficiency and song structure. The characterization of functional links between vocal tract morphology and song, together with field playback studies, is providing insight into relationships between morphological adaptation, vocal diversification, and reproductive isolation.
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Vocal tract function in birdsong production: experimental manipulation of beak movements (with W. J. Hoese, N. C. Boetticher, and S. Nowicki), Journal of Experimental Biology (2000)
Kinematic analyses have demonstrated that the extent to which a songbird's beak is open when...