Vocal plasticity in captive black-capped chickadees: the acoustic basis and rate of call convergence

During the winter months, the acoustic structure of the 'chick-a-dee' call of black-capped chickadees, Parus atricapillus, is similar among flock members but varies significantly between different flocks. To investigate the process of within-flock convergence through which these differences arise, an experimental flock of birds previously unfamiliar with each other was established and maintained in captivity. The vocal behaviour of each individual was monitored over several weeks. Acoustic analyses revealed that significant vocal convergence occurred in less than 1 week after the birds were initially exposed to each other. No single individual appeared to provide a vocal model that other birds copied. Acoustic differences appeared in the spectral structure of the D-note of this complex call, especially in the frequency difference between adjacent overtones and in the bandwidth. Both of these acoustic features are attributable to specific physiological mechanisms of production. The significance of vocal plasticity in chickadees and its relationship to production and perception are discussed. © 1989.

Duke Scholars

Author Stephen Nowicki Biology