title: Migration and the evolution of duetting in songbirds.
abstract: Many groups of animals defend shared resources with coordinated signals. The best-studied of these signals are the vocal duets produced by mated pairs of birds. Duets are believed to be more common among tropical-breeding species, but a comprehensive test of this hypothesis is lacking, and the mechanisms that generate latitudinal patterns in duetting are not known. We used a stratified sample of 372 songbird species to conduct the first broad-scale, phylogenetically explicit analysis of duet evolution. We found that duetting evolves in association with the absence of migration, but not with sexual monochromatism or tropical breeding. We conclude that the evolution of migration exerts a major influence on the evolution of duetting. The perceived association between tropical breeding and duetting may be a by-product of the migration-duetting relationship. Migration reduces the average duration of partnerships, potentially reducing the benefits of cooperative behaviour, including duetting. Ultimately, the evolution of coordinated resource-defence signals in songbirds may be driven by ecological conditions that favour sedentary lifestyles and social stability.
authors.affiliation: Departamento de Biología, Universidad de Puerto Rico, , PO Box 9000, Mayagüez PR 00681-9000, Puerto Rico, Department of Zoology, University of Melbourne, , Melbourne, Victoria 3010, Australia.
authors.forename: David M
authors.initials: DM
authors.lastname: Logue
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Hall
mesh_terms: D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D005075:Biological Evolution; D003299:Cooperative Behavior; D005843:Geography; D010802:Phylogeny; D010858:Pigmentation; D012098:Reproduction; D012727:Sex Characteristics; D020308:Songbirds / Q000145:classification / Q000502:physiology*; D014828:Vocalization, Animal / Q000145:classification / Q000502:physiology*
keywords: comparative method; cooperation; duet; migration; sexual dichromatism