Meeting Abstract
P2.8 Monday, Jan. 5 Heterospecific Vocal Mimicry in Cassin’s Finch (Carpodacus cassinii) PARKER, S.D.*; SEWALL, K.B.; HAHN, T.P.; University of California Davis; University of North Carolina Chapel Hill; University of California Davis sdparker@ucdavis.edu
Heterospecific vocal mimicry (HVM) is widespread among oscine songbirds. In some cases songbirds mimic entire elements from other species repertoires and use signals in the same social contexts. For example, studies have established that HVM can function for deception of hosts by brood parasites or predator evasion by eliciting mobbing behavior among heterospecifics. In other cases, songbirds include mimicked elements in their songs. It has been asserted that HVM in song is the outcome of passive processes like the accumulation of learning mistakes to generate large repertoires that include imitations. Alternatively, in other mimicking species, HVM may be under sexual selection because females assess song complexity as a cue for male quality. I investigated song complexity and expression of HVM in Cassins finch (Carpodacus cassinii), a North American mimicking species.
Cassins finch is an excellent model to test the sexual selection hypothesis because males mimic many different species and insert those imitations in songs used to attract females. My analysis of Cassins finch song reveals that within a bout, males generate the greatest variation through manipulation of heterospecific imitations in a single song theme. Further, these imitations are placed at the end of songs, where the type and syntax of these elements generate variation on the theme. These data suggest that Cassins finch males control song complexity largely through appropriation of elements from other species. Thus it is possible that sexual selection through female choice is driving males to produce complex songs achieved through expression of heterospecific imitations. This interpretation is consistent with the observation that males seldom sing during aggressive encounters with other males, but frequently do so when interacting with females.
