Aug. 28 (UPI) --It's difficult to track birds flying across the sky in the dark of night, but every fall and spring, millions of birds migrate through the night. Weather radar can offer a spotty ...

In the fall, white-crowned sparrows (Zonotrichia leucophrys gambelii) fly some 4,300 kilometers from their breeding grounds in Alaska to their winter homes in southern California.

While ultraviolet fluorescence is common in birds, butterflies and sea creatures, scientists haven’t often observed it in mammals. By Veronique Greenwood One spring night in Wisconsin, John ...