|The Geography of Song Type Repertoires|
|Peter C. Mower, Samantha W. Krause, David M. Logue. University of Lethbridge, Lethbridge, Alberta, Canada
Avian song repertoires are a model of human vocabularies because both systems comprise diverse, learned signal sets. The functional significance of signal diversity in birdsong, however, remains a mystery. We attempt to shed light on the functions of song repertoires by using continuous audio recordings and GPS locations from male Adelaide’s Warblers to (1) describe spatial patterns of song type use within territories and (2) test a prediction of the hypothesis that birds use shared song types to communicate with neighbors. The descriptive part of the study maps song type use within territories to identify spatial patterns of repertoire use. We interpret non-random patterns of use as a potential indicator of functional variation among song types. The hypothesis-driven part of the study tests if birds are more likely to sing song types that are shared with a neighbor when they are closer to that neighbor’s territory border. Increased use of shared song near a border would be interpreted as support for the hypothesis. This study combines bioacoustic and geographic techniques with a large, observational dataset to offer a fresh perspective on the function of song repertoires.