“Responses of male tropical mockingbirds to variation in within-song and between-song versatility”

C.A. Botero and S.L. Vehrencamp

Although male tropical mockingbirds (Mimus gilvus) normally sing with high vocal versatility, they are sometimes highly repetitive during male-male encounters. We tested the hypothesis that more repetitive singing represents a stronger threat and generates a stronger aggressive response by simulating conspecific singers with playback and assessing male response. Focal birds showed stronger responses to simple songs (i.e. composed of a single note type) than to variable ones and to high song switching rates than to low ones. In a manuscript recently accepted by the Auk (expected date of publication January 2007) Sandra Vehrencamp and I discuss the possibility that the signal value of variation in vocal versatility in the tropical mockingbird lies in the mediation of territorial conflicts, the attraction of female partners and/or the mediation of conflicts over access to reproductive females.