Birds' songs change over time
JUST as the Bee Gees' disco style sounds antique compared to hip-hop, birdsong can also go out of fashion. Such stylistic changes may help explain how mating barriers arise, eventually leading to new species.Derryberry received a research award in 2004 from the American Ornithologists' Union for "The impact of culture and selection on vocal performance: implications for song evolution."
Behavioural ecologists have long known that some songbirds develop local dialects, and that individual birds respond more strongly to their own dialect than to a foreign one. Less is known about how, or how quickly, such differences arise.
To study how a dialect changes over time, Elizabeth Derryberry, a behavioural ecologist at Duke University in Durham, North Carolina, compared recordings of male white-crowned sparrows' song from 1979 - when the Bee Gees topped the charts - and 2003. The modern song, she found, was slower and lower in pitch.
Ilustration courtesy of WhatBird.com