Ostriches are the largest living birds and cannot fly, but they run quickly.

The longer version

An ostrich sits far past the size limit for flapping flight. Wing loading rises with size, and beyond roughly twenty kilograms a bird cannot generate enough lift without running to launch. The leg muscles were redeployed for running instead, and the foot was reduced to two toes on a thick pad.

Stride length is the key. A long tendon stores and returns energy like a spring, so speed comes relatively cheap. Ostriches hold a fast pace for a long time rather than sprinting briefly, and they use the wings as rudders when turning. The breastbone keel, where flight muscles anchor, is nearly gone.

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.