A bird also has muscles that are thin and light. A bird uses a lot of oxygen and energy while in flight. They must eat frequently to replenish their energy reserves. It has a heart that pumps very fast to to keep the blood supply speeding throughout its body. A bird's feathers are also virtually weightless, yet warm and strong which helps while it's flying.
Bird migration is among the most miraculous and mysterious of natural phenomena.
Migrations are seasonal movements of wildlife from one habitat to another. Migrating birds usually follow well established routes between environments. Vocabulary - Type your answer in the box. Your score is out of 10. Just as we need to make preparations for a long trip by planning a route and deciding what to take, birds also need to prepare so that they will arrive in good shape at their correct destinations.