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.
After hibernation, chipmunks go to find love, then get ready for next hibernation.
Hibernate is a verb. The noun form is hibernation.
The two types of hibernation are true hibernation, which involves a drastic drop in body temperature and metabolism, and torpor, which is a state of reduced activity and metabolism without a significant drop in body temperature.
Birds do not hibernate. Instead, they use a variety of mechanisms to survive colder climates, such as migrating to warmer areas, fluffing up their feathers to trap heat, or lowering their metabolic rate to conserve energy during colder months. Some birds, like chickadees, may enter a state of torpor on cold nights to save energy, but this is different from hibernation.