Sparrows Change Their Tune to be Heard in Noisy Cities
http://www.sciencedaily.com/releases/2012/04/120402162710.htm
Researchers studied the songs sung by male white-crowned sparrows in the Presidio district of San Francisco from 1969 to today. In 1969 the sparrows sang three different songs at different pitches, as San Francisco got louder the birds lower pitch song disappeared and it seemed that only the loudest song would remain. But the birds came up with new songs to be heard over the noises of the busy city. The researchers also tested the sparrow’s reactions to recordings of the old and new songs being played. The Sparrows didn’t think anything of the old songs and basically ignored them, but the new songs were taken as threats and treated as such.
This could affect bird researchers and watchers as well as all the people who enjoy hearing birds sing.
