What feathers overlap and cover the body of a bird?

The feathers that overlap and cover the body of a bird are primarily called contour feathers. These feathers provide the bird with shape and streamline its body for flight, while also offering insulation and protection. Beneath the contour feathers, birds have down feathers for additional insulation, and specialized feathers like flight feathers on the wings and tail aid in aerodynamics. Together, these feather types create a protective and functional covering for the bird.