There are more types of birds in nature than mammals. Birds are warm blooded. All birds have feathers. Many birds can fly but not all of them  like the penguin, ostrich, and imu. One third of birds migrate to warmer areas in the winter. Hummingbirds feed their young 50 times per day. Some birds are birds of prey like the red tailed hawk.
Source: Bill Nye The Science Guy - Birds by Disney