A primary function of male bird song is to attract females as mates. However, not all songs are equally effective at achieving this goal. For example, females are more likely to mate with males that produce longer songs or more kinds of songs, presumably because a male's ability to do so corresponds to some aspect of his quality as a potential mate. This project investigates a new mechanism by which females use song to assess males as potential mates: the ability of males to produce songs that are hard to sing. When birds sing they produce pure tone sounds by opening their beaks to produce high frequency tones and by closing their beaks to produce low frequency tones making it difficult to produce trilled songs that are both broadband and rapid. "Vocal performance" refers to the ability of males to cope with this difficulty and may reflect male quality. This project proposes to test the hypothesis that females use vocal performance to choose mates because it reflects male quality, to investigate a mechanism by which females are able to discriminate such subtle features of song, and to test a key prediction of how beak movements affect vocal performance. The broader impacts of this project are to foster the professional development of women in science, disseminate science to the public and provide biological data important for conservation of an endangered habitat.
