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Biol Lett. Oct 23, 2010; 6(5): 589–592.
Published online Apr 14, 2010. doi:  10.1098/rsbl.2010.0165
PMCID: PMC2936152
Persistence of song types in Darwin's finches, Geospiza fortis, over four decades
Eben Goodale* and Jeffrey Podos
Department of Biology, Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003, USA
*Author and address for correspondence: Section of Ecology, Behavior and Evolution, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA (eben.goodale/at/gmail.com).
Received February 20, 2010; Accepted March 22, 2010.
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
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