Birds
Falcon
Falconidae · also called falcons
A falcon is what you get when the same job — catching and killing other animals in the air — is done by a bird from an entirely different branch of the family tree. Falcons look like hawks, hunt like hawks, and are not hawks; their closest relatives are parrots and songbirds. And one of them, the peregrine, in its hunting dive, is the fastest animal on Earth.
Overview
Falcons are the family Falconidae, around 65 species, on every continent except Antarctica. They have long pointed wings, fast direct flight, and, in the true falcons, a notched beak — the tomial tooth — for severing prey’s necks, which hawks and eagles lack. The family includes the bird-hunting true falcons (peregrine, gyrfalcon, lanner), the small rodent- and insect-eating kestrels, and the odd ground-walking caracaras.
The stoop
In level flight a peregrine is merely fast. Its record speed comes in the stoop — climbing high, folding its wings, and dropping. Radar and camera studies have clocked peregrines over 380 km/h in the dive, faster than any other animal, striking prey with a clenched foot at the bottom.
No nest of their own
Falcons build no nest, laying eggs on a bare cliff ledge, in a tree hollow, on a building, or in another bird’s abandoned stick nest — which is why city peregrines and kestrels do so well on skyscrapers and bridges.
Crash and recovery
The peregrine was wiped out across the eastern US and much of Europe by DDT thinning its eggshells, then recovered through a DDT ban and a large captive-breeding programme, leaving the US endangered list in 1999. Falconry, the hunting partnership between people and falcons, is at least 3,000 to 4,000 years old.
Status
Falcons as a family are Not Evaluated. The peregrine and several kestrels are common or recovering, but the saker falcon is declining sharply from trapping and power-line electrocution, and the Mauritius kestrel was brought back from just four known birds in 1974.
Falcon: common questions
How fast can a peregrine falcon really fly?
In level flapping flight a peregrine is fast but not exceptional, cruising around 40 to 60 km/h and sprinting to perhaps 110. Its record-breaking speed comes only in the stoop, the near-vertical hunting dive in which it climbs high, then folds its wings tight and drops on a bird below. In that dive, measured with radar, aircraft, and cameras mounted on tame falcons diving alongside skydivers, peregrines have exceeded 380 km/h, and one much-cited trial recorded 389. This makes the peregrine the fastest animal on the planet. The falcon strikes the prey with a clenched foot at the bottom of the dive, often killing it on impact.
Are falcons related to hawks and eagles?
No, and this was a genuine surprise when the genetic data came in. For centuries falcons were grouped with hawks, eagles, kites, and vultures as birds of prey, on the strength of their hooked beaks, sharp talons, and meat-eating habits. But DNA studies in the 2000s and 2010s showed that falcons sit on a completely different branch of the bird family tree, with their closest relatives being the parrots and the perching birds, or songbirds. Everything falcons share with hawks evolved independently in response to the same job of catching and killing other animals, an example of convergent evolution.
What is the difference between a falcon and a kestrel?
A kestrel is a type of falcon, one of a group of small, often reddish-brown falcons within the family Falconidae. What sets kestrels apart from the larger true falcons is mainly diet and hunting style. Kestrels feed largely on voles, mice, lizards, and insects taken on the ground, and they are famous for wind-hovering, holding station in mid-air with rapid wingbeats and a motionless head while scanning the grass below. The bigger falcons, such as the peregrine, gyrfalcon, and lanner, specialise in catching other birds in fast flight and rarely hover. Kestrels also show more difference in plumage between the sexes.
Why do peregrine falcons live in cities now?
Cities suit them remarkably well. Tall buildings, bridges, and towers stand in for the cliff ledges peregrines naturally nest on, and there is no shortage of prey, since city pigeons, starlings, and other birds are abundant year round. There are few predators of adult peregrines in a city, and the birds are legally protected and often actively encouraged with nest boxes. Urban peregrine populations began establishing in the 1980s as the species recovered from the DDT era, and many major cities on several continents now have resident pairs, some watched by webcams during the breeding season.