The basic answer is they have feathers and also bones that are hollow, making them light and still strong. But there is more to the story of feathers than just flying. In fact bird feathers have a lot of different uses.

What are birds feathers coated with?

To achieve that, aquatic birds coat their feathers with an oily substance known as preen oil, which is secreted from a gland on their rumps, above their tail feathers. This gland, known as the uropygial or preen gland, is present in nearly all birds, but its shape and size varies among species.

What is the feather of a bird?

feather, the component structure of the outer covering and flight surfaces of all modern birds. Unique to birds, feathers apparently evolved from the scales of birds’ reptilian ancestors.