Variation in chick-a-dee calls of tufted titmice, Baeolophus bicolor: note type and individual distinctiveness

The chick-a-dee call of chickadee species (genus Poecile) has been the focus of much research. A great deal is known about the structural complexity and the meaning of variation in notes making up calls in these species. However, little is known about the likely homologous "chick-a-dee" call of the closely related tufted titmouse, Baeolophus bicolor. Tufted titmice are a prime candidate for comparative analyses of the call, because their vocal and social systems share many characteristics with those of chickadees. To address the paucity of data on the structure of chick-a-dee calls of tufted titmice, we recorded birds in field and aviary settings. Four main note types were identified in the call: Z, A, D(h), and D notes. Several acoustic parameters of each note type were measured, and statistical analyses revealed that the note types are acoustically distinct from one another. Furthermore, note types vary in the extent of individual distinctiveness reflected in their acoustic parameters. This first step towards understanding the chick-a-dee call of tufted titmice indicates that the call is comparable in structure and complexity to the calls of chickadees.