A duck can slip into a pond, tip its body, and emerge with a fish in its bill within minutes; a seabird may circle, dive, and abort the attack again and again before landing the same prize. Speed in the air, it turns out, is a poor proxy for efficiency in water.What looks like clumsiness is mostly design trade‑off. Ducks carry webbed feet, dense plumage and a body plan tuned for buoyancy and stabl...More