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Biol Lett. 2010 October 23; 6(5): 589–592.
Published online 2010 April 14. doi:  10.1098/rsbl.2010.0165
PMCID: PMC2936152

Persistence of song types in Darwin's finches, Geospiza fortis, over four decades

Abstract

Learned bird songs evolve via cultural evolution, with song patterns transmitted across generations by imitative learning. In Darwin's finches of the Galápagos Islands, males learn songs from their fathers, and song types can be maintained across multiple generations. However, little is known about the time frame over which specific song types are preserved, in the face of copy errors and corresponding modifications to song structure. Here we investigate cultural evolution in songs of male Geospiza fortis, at Academy Bay, Santa Cruz Island, comparing songs recorded in 1961 by R. Bowman (20 individuals) to those recorded in 1999 by J. Podos (16 individuals). For each individual, we characterized four timing and six frequency parameters, and assessed inter-individual variation in song structure using multivariate analysis. Several 1961 song types persisted into 1999, some with remarkable fidelity. Variation among song types was extensive during both years, and we detected no changes in 10 vocal parameters across the sampling period. These results illustrate temporal continuity in a culturally acquired trait, and raise questions about mechanisms that promote stability in song structure.

Keywords: bird song, cultural evolution, Darwin's finches, Galápagos Islands, Geospiza fortis

Articles from Biology Letters are provided here courtesy of The Royal Society