title: Transcontinental latitudinal variation in song performance and complexity in house wrens (Troglodytes aedon).
abstract: There is growing interest in latitudinal effects on animal behaviour and life history. One recent focus is on birdsong, which is hypothesized to be more elaborated or complex in the north temperate zone compared with the tropics. Current evidence is mixed and based on cross-species comparisons, or single species with restricted distributions. We circumvent these limitations using a transcontinental sample of 358 songs from house wrens (Troglodytes aedon) at 281 locations spanning more than 100° of latitude (52° N-55° S) across the Americas. We found a significant latitudinal gradient in several basic elements of song performance and complexity between north temperate and tropical populations. Furthermore, we document convergence in song patterns between populations at higher latitudes in the Northern and Southern Hemispheres. Effects were strongest for the number of elements in a song, and the rate of element production, both increasing towards the poles, with similar but weaker effects for other song dimensions (e.g. number of unique elements, trills and trill rate). We consider possible causes related to variable habitats and morphology, concluding that the shorter breeding seasons at higher latitudes in both hemispheres may favour greater song elaboration to mediate territory competition and mate choice.
authors: Behaviour and Evolution Research Group, Department of Psychology, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4.
authors: Chinthaka
authors: C
authors: Kaluthota
authors: Behaviour and Evolution Research Group, Department of Psychology, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4.
authors: Benjamin E
authors: BE
authors: Brinkman
authors: Behaviour and Evolution Research Group, Department of Psychology, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4.
authors: Ednei B
authors: EB
authors: Dos Santos
authors: Behaviour and Evolution Research Group, Department of Psychology, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4 Department of Biology, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, Canada E3B 5A3 d.rendall@unb.ca.
authors: Drew
authors: D
authors: Rendall
mesh_terms: D063147:Animal Distribution; D000818:Animals; D002489:Central America; D008297:Male; D009656:North America; D020308:Songbirds / Q000502:physiology*; D013020:South America; D013731:Territoriality; D014828:Vocalization, Animal
keywords: geographical variation; latitudinal gradient; sexual selection; song complexity; song performance; songbirds