Peregrine Falcon

The peregrine falcon is the fastest animal that has ever been measured. In a hunting dive it reaches nearly 400 km/h — faster than a Formula 1 car, faster than a skydiver in freefall — and it does this to catch a pigeon.

Overview

The peregrine is the most widely distributed bird of prey in the world, found on every continent except Antarctica and on many oceanic islands. Its name means “wanderer” or “pilgrim,” a reference to the long migrations some northern populations make. It hunts in open airspace — over coasts, marshes, moorland, farmland, and, more and more, over cities.

The stoop

A peregrine hunts by climbing to a height above its prey, then folding its wings into a teardrop shape and stooping — dropping in a controlled dive. As it accelerates it tucks its feet under its tail and steers with tiny adjustments of the wingtips and tail. The dive ends with a strike: the falcon usually hits the target bird with a closed foot, the impact alone often enough to kill it, then wheels around to snatch the body out of the air or retrieve it from the ground.

Surviving that speed requires a purpose-built body:

• Nasal baffles — small bony cones inside the nostrils that break up and slow the 400 km/h airflow so the bird can still breathe.
• A nictitating membrane, a translucent third eyelid, that wipes and protects the eyes without stopping the falcon from seeing its target.
• Dense, stiff, overlapping feathers and a small, heavy, streamlined frame that stays stable and does not flutter apart under the forces of the dive.

Vision and diet

Peregrine eyesight is roughly eight times sharper than a human’s — it can lock onto a pigeon from over a kilometre away. The diet is almost exclusively birds caught in flight: pigeons and doves above all, plus starlings, ducks, waders, and songbirds, with the occasional bat. A pair will cache surplus kills on a ledge to eat later.

Reproduction

Peregrines do not build nests. They lay their eggs in a simple scrape on a cliff ledge, a quarry face, or a building, returning to the same site year after year with the same mate. The female lays three or four eggs, and both parents incubate them for about a month. Chicks fledge at six weeks and spend several more weeks learning to hunt, chasing each other and dropping objects to catch in mid-air.

Conservation

The peregrine is listed as Least Concern with an increasing population — but only because of a deliberate rescue.

In the mid-20th century the pesticide DDT spread through food chains and caused peregrines (like bald eagles) to lay eggs with shells too thin to survive incubation. The species was wiped out across the eastern United States and crashed in Europe. After DDT was banned, conservationists bred peregrines in captivity and released thousands from cliff sites and, famously, city buildings. Populations recovered so fully that the peregrine was removed from the US endangered list in 1999. It remains a conservation icon and a fixture of urban wildlife.