Several hummingbirds have already been spotted in southern U.S. states. Here's when to expect them in New York.

Animal migration ... swarms of locusts are under the influence of the hormone serotonin. The connections between day length, annual reproductive cycle and migration are now well established in ...

Now one of the questions is: why are North American grassland bird populations shrinking? Is it something happening on their breeding grounds, on their southern wintering grounds, or at stopover sites ...