A new study by biologists from the University of California, Berkeley, and Missouri State University in Springfield, however, documents songs in East African sunbirds that have remained nearly unchanged for more than 500,000 years, and perhaps for as long as 1 million years, making the songs nearly indistinguishable from those of relatives from which they’ve long been separated.
“If you isolate humans, their dialects quite often change; you can tell after a while where somebody comes from. And song has been interpreted in that same way,” said senior author Rauri Bowie, UC Berkeley professor of integrative biology and a curator in the campus’s Museum of Vertebrate Zoology. “What our paper shows is that it’s not necessarily the case for birds. Even in traits that should be very labile, such as song or plumage, you can have long periods of stasis.”