I am strong and thick and can really do the trick, especially with a lot of grit.
Millions of barbs on every vane, without me winter would be a pain.
My shape gives birds something really neat: a lift to get them off their feet.
Space inside to keep me light, struts that brace to give me might.
I am not a friend of water - that is a fact. And I am a big part of the preening act.
Two small holes are the only clues that we are inside a bird, hidden from view.
Depending on what a bird might eat, I can double my size -that is quite a feat!
In some birds we are found almost everywhere. We are hooked to the lungs and filled up with air.