Urban birds are changing their tunes. It's hard for them to communicate over the cacophony of the city, so they're adapting by ditching their "rich mix of enchanting melodies and calls" in favor of "a strangely depleted music – abrupt, high-pitched and sometimes ear-piercing."
The story's on BLDGBLOG. This may be a change in behavior, and not in genes, but it reminds us of the famous case of the Peppered Moth, which evolved darker wings to blend in with the dirty environment of the English Industrial Revolution.
Photo from Angelrays.