A bird is an animal with feathers and wings. Most birds can fly. Birds have two legs. They can walk, run, or hop.

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All birds have a backbone. It is also called a spine. Birds have many hollow bones. Hollow bones have empty space inside. They make a bird's body lighter. That helps birds fly.

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Birds are warm-blooded. They make their own body heat.

 

Birds lay eggs. The shells are hard. Birds keep the eggs warm. How? They sit on them until the eggs hatch! Then the bird takes care of its chicks.