Penguins cannot fly, but they swim underwater using wings shaped like flippers.

The longer version

A penguin wing has lost the long, flexible hand bones that most flying birds use. The bones are flattened and partly fused into a stiff blade. Underwater the bird beats that blade and generates lift on both the upstroke and the downstroke, so it effectively flies through water, a fluid far denser than air.

The density is exactly what makes the trade worthwhile. Water gives enough resistance for a short, stiff wing to push against, while air would not. On land the same limbs are useless for flight, which is why penguins walk upright and toboggan on their bellies. Their feathers are short and packed tightly into a smooth surface.

Where this entry sits

Here you will find feathered trivia about flight, migration, nests, eggs, and the songs birds sing. Expect short surprising facts on penguins, owls, hummingbirds, and other familiar birds from gardens, forests, wetlands, and distant coastlines. The full list sits on the Birds page, where every entry is listed in order.