Which bird reaches over 300 km/h in a hunting dive?

The peregrine falcon reaches over three hundred kilometres an hour in its stoop, a near-vertical dive onto prey in mid-air, which makes it the fastest animal in any medium. The speed comes from gravity as much as muscle: the bird climbs high, folds its wings tight against the body to cut drag to a minimum, and effectively falls in a controlled, steerable shape. Surviving that requires anatomy most birds lack. Bony tubercles in the nostrils are thought to slow the airflow entering the airways so the falcon can still breathe at speed, and a third eyelid sweeps the eye clear while keeping it protected. The strike itself is usually a blow from a clenched foot rather than a grab, killing or stunning the target on impact so the falcon can catch it as it falls. Peregrines have adapted well to cities, hunting pigeons and nesting on tall buildings that stand in for cliffs.

In level flapping flight the peregrine is fast but not exceptional; the record belongs entirely to the dive.