Birds Birds are some of the most amazing animals on earth. Most have the ability to fly. Some use ground travel. Some use claws, others use only their beaks. Birds come in many varieties of colors and sizes. Birds are warm-blooded, egg-laying creatures from the aves class. Along with the obvious feathers and wings, birds have other adaptations for flying such as a wide keel on the sternum, with large wing muscles attached, air spaces and sacs throughout the body and bones, to decrease their weight, and they have various bone fusions and reductions to strengthen and streamline their body. There are more than 8700 species of birds. Their habitats range from icy shores of Antar