How do you describe a bird's body covering?

A bird's body covering is primarily made up of feathers, which serve various functions such as insulation, waterproofing, and aiding in flight. Feathers come in different types, including contour feathers that shape the bird's body, down feathers for insulation, and flight feathers found on the wings and tail. The coloration and patterns of feathers can also play a role in camouflage, mating displays, and species identification. Additionally, some birds may have a layer of down under their feathers for extra warmth.