Listen to your favorite National Geographic news daily, anytime, anywhere from your mobile phone. No wires or syncing. Download Stitcher free today.
Monday, November 23, 2009 |
Monday, November 23, 2009 |
Photo: Birds That Sing Together Scare off InvadersThe longer the pairs stay mated, the more forceful and harmonious their song becomes, the study adds. Photograph courtesy Michelle Hall
|
ADVERTISEMENTNATIONAL GEOGRAPHIC'S PHOTO OF THE DAY |
|
ADVERTISEMENT
|