This is bird note.

When a bird takes wing, it leaves most of us other creatures earthbound.

Birds have evolved not only wings, but many other adaptations that make it possible to fly.

First of all, feathers.

Feathers provide insulation, waterproofing, and a means to fly.

And they're extraordinarily lightweight.

Other features also help minimize the pull of gravity, mostly by reducing body weight.

Birds have very light, honeycombed, or hollow bones.

And instead of a weighty mouthful of jawbones and teeth,

birds have evolved a supremely light and serviceable beak.

What birds eat also helps them stay light for flight.

Most consume energy-packed foods rich in calories, like seeds, fruits, and meat. These are foods that add as little as possible to a bird's payload

and deliver a lot of bang for the buck. And what birds eat is processed rapidly, so they aren't weighed down by waste.

All of these adaptations for flight, and a pair of wings, too.

For Bird Note, I'm Michael Stein.