Falcon

Falcons make up the genus *Falco*, a group of about 40 species of birds of prey. You’ll find them on every continent except Antarctica, though fossil evidence shows that similar raptors lived there during the Eocene. Their trademark is a set of thin, tapered wings built for blistering speed and sharp turns. Unlike hawks and eagles—which belong to a different family and kill with their feet—falcons dispatch their prey using a special notch on their beak called a tomial “tooth.”

Young falcons, in their first year of flight, have longer flight feathers that give them a more general-purpose wing shape, like a broadwing. This helps them learn the aerial skills they’ll need as adults without being as specialized. The largest falcon is the gyrfalcon, reaching up to 65 cm (26 in) in length; the smallest is the pygmy falcon, at just 20 cm (7.9 in). Like many raptors, females are typically larger than males—a trait called sexual dimorphism—which lets the pair hunt a wider range of prey.

Falcons have exceptional vision; one species’ eyesight is 2.6 times sharper than a human’s. They’re also incredibly fast fliers. Peregrine falcons have been recorded diving at 320 km/h (200 mph), and the fastest measured dive hit 390 km/h (240 mph), making them the fastest-moving animals on Earth.

The genus *Falco* was first described by Carl Linnaeus in 1758, with the merlin as the type species. The name comes from Late Latin *falco*, derived from *falx* (“sickle”), a reference to the bird’s claws. A male falcon is called a tercel or tiercel—from the Latin *tertius* (“third”), based on the old belief that only one in three eggs produced a male, or because males are about a third smaller than females. A downy chick, especially one raised for falconry, is an eyas (from a misdivision of Old French *un niais*, meaning “nestling”). The practice of hunting with trained falcons is falconry.

The fossil record for falcons is patchy. For years, the oldest fossils assigned to the genus were from the Late Miocene, less than 10 million years ago. But as of 2021, the oldest known falconid fossil dates back about 55 million years. Based on where living and fossil *Falco* species are found, falcons likely originated in North America, Africa, or possibly the Middle East or Europe. They aren’t closely related to other birds of prey; they belong to the group Australaves, whose nearest relatives are parrots and songbirds.

Falcons can be roughly split into three or four groups. The first includes kestrels—small, stocky birds with brown upperparts, often showing sexual dimorphism. Three African species are gray instead. Kestrels mostly eat terrestrial vertebrates and large invertebrates like rodents, reptiles, and insects. The second group is the hobbies and their relatives, which are slightly larger, have dark slate-gray plumage, and nearly always a black patch on the cheek (the malar area). They mainly hunt smaller birds. The third group includes the peregrine falcon and its kin—powerful, fast birds with black malar areas (except in some pale color morphs) and often a black cap. They’re medium gray above, with horizontal barring below, and their tails are uniformly dark gray with faint black bands and small white tips. These large falcons feed on mid-sized birds and terrestrial vertebrates. Very similar are the hierofalcons (or “hawk-falcons”), which have more reddish or brown colors and a hawk-like pattern of blotches or arrowhead marks on their undersides.