Forget bird watching; next time you spot a hummingbird, listen.

Most of us pause to gaze at the tiny birds’ impressive mid-air hovering, part of their hunting behavior, but males of some hummingbird species generate loud sounds with their tail feathers while courting females.

Now, for the first time, the cause of these sounds has been identified: a paper published in the Sept. 9, 2011, issue of Science reveals that air flowing past the tail feathers of a male hummingbird makes his tail feathers flutter and thereby generate fluttering sounds.

Watch a video of hummingbird tail feathers in an wind...