Everything about birds appears to be designed for flight. For example, the shafts of wing feathers, it's bones and the muscles.
It resembles what engineers call a foam-sandwich beam. It has a pithy interior and a rough exterior. Engineers have studied feather shafts, and foam-sandwich beams are used in aircraft.
What about the bones?
It's bones are also amazingly designed. Most are hollow, and some maybe strengthened by internal struts in a form engineers call the Warren girder. Interestingly, a similar design was used in the wings of the space shuttle.
Muscles?
Well, a pilot balance modern aircraft by adjusting a few flaps on the wings and tail. But a bird uses some 48 muscles in its wing and shoulder to change the configuration and motion of its wings and individual feather, doing so several times a second. No wonder that avian aerobatic ability is the envy of aircraft designers!
