Some of them do. Not most of them. Most of them fly away with there babies to a warmer location.
It's because of hibernation.
The same way it helps a human.. They Get refreshed!
because of the hibernation
Terns migrate, they do not hibernate, Birds cannot hibernate.
When bears go to sleep in the winter, it is called Hibernation. Squirrels, birds, and other animals who dislike the cold do the same thing.
Nightingales normally come out of hibernation in the spring after spending the winter in southern Africa. The nightingale is traditionally thought to announce the coming spring time.
Note that most birds do not hibernate, although it does happen with penguins. Hibernation is by definition a period of inactivity; any hibernating animal does not eat.
There are many animals besides bears that go into hibernation every year. Some species of bat hibernate as do hedgehog, squirrel, dormice and even some birds.
do you mean migration?? And if so migration is moving to a different area birds migrate south for warmer weather in the winter months. Hibernation is what bears do, they just sleep all winter.
true hibernation and pseudo hibernation
After hibernation, chipmunks go to find love, then get ready for next hibernation.
Hibernate is a verb. The noun form is hibernation.