Parus major songbirds are thought to be relatively similar throughout Europe. But comparing DNA data from great tits in the United Kingdom with those in the Netherlands revealed key genetic differences between the two populations. The analysis, published in the Oct. 20 Science, linked those genetic differences to a slightly longer beak in U.K. birds seen over the last few decades. Since beak length is known to be associated with food availability, the researchers speculate that the U.K. great tits may be adapting to the widespread use of bird feeders in the country.

In other studies, bird beaks have been shown to be sensitive to the environment and capable of rapid change, says coauthor Mirte Bosse, an ecologist at Wageningen University & Research in the Netherlands. This new study demonstrates that even in our own backyards, small evolutionary changes may be happening, she says.