How do birds fly, and why do some birds not fly at all?
Wings & Deals
How do birds fly, and why do some birds not fly at all?
Look up. A sparrow leaps off a branch, and instead of falling like a dropped stone, it climbs the air. That's the trick we're chasing today. How does a thing made of bones and feathers shrug off gravity and go up? And — here's the twist — why do some birds, perfectly good birds with wings and all, never bother to fly at all?
Start with the wing, because the wing is the whole secret. Look at it edge-on: the top is gently humped, the bottom is flatter. When a bird pushes this shape forward through the air, the air splitting over it has to hurry across the curved top. Faster-moving air presses down a little less. So the air below pushes up harder than the air above pushes down. That gentle upward shove has a name: lift.
