Vocal mimicry and the evolution of bird song

Abstract

Vocal mimicry in birds appears to have evolved to augment the songs of some species. Its incorporation into the songs of lyrebirds depends on the mimic using the model's calls at a time when they have no biological significance to the model and on the physical characteristics of the model's calls being sufficiently like those of the mimic to convey the same information to territorial rivals and females as do the mimic's own calls.

The Ptilonorhynchidae on the other hand use mimicry of predators to enhance the threatening nature of a song that cannot include loudness for this purpose because lengthy display at a bower jeopardizes the bird.

Mimicry is normally suppressed by the need for specific identification but may emerge as a displacement activity where a species is exposed to predation or disturbance as a result of the need to make a loud and continuous noise and can be retained in song if it is biologically advantageous.

Studies of the Menuridae and Atrichornithidae give examples of the selective development of own song with or without mimicry in relation to the timing of breeding and geographical distribution of mimic and model.