Cultural Evolution and Long-Term Song Stability in a Dialect Population of Brown-Headed Cowbirds

[摘要] Abstract. Knowing the extent to which the acoustic structure of songs is temporally stable is essential to understanding how cultural evolution affects song dialects in oscines. The acoustic structure of the most prevalent variant of the flight-whistle song recorded from male Brown-headed Cowbirds (Molothrus ater) in the Mammoth dialect (Mammoth Lakes, California) from 2005 to 2009 differed significantly and consistently from whistles recorded in 1989 and 1978–1985. The most common whistle variant in the 2005–2009 sample had structural features absent from whistles described in the earlier studies and overall was produced at a consistently lower acoustic frequency. Besides the emergence of this new variant sometime between 1989 and 2005, the prevalence of other variants of the whistle also changed from 1978 to 2009. Changes reported in other studies of cultural evolution in oscines have been based on lower-level structural elements (notes and syllables), whereas we found that entire songs appear to have e...

[学科分类] 动物科学

[关键词] song dialects;Brown-headed Cowbirds;cultural evolution;cultural stability;Molothrus ater