If you look up toward the sky, you might notice a flock of birds flying overhead. Why do the birds do this? They might be looking for food or for a place to rest, or they might be migrating. Some birds, such as the whooping crane, fly long distances when they migrate.
In North America, migrating birds travel south for the winter and north for the summer. You might be surprised to learn that migration is not an instinctive behavior. Young cranes, for example, must learn from their parents how to migrate.