Falcon, common name for members of a genus containing 38 species of birds of prey, and for other species of the same family. They are characterized by their long wings; their method of hunting, which is to rise above and swoop down on their prey; and by a notch on the upper part of the bill (mandible), which is hooked. The feet are powerful, with long, curved, sharp talons. As the birds drop on their prey, they seize and hold it, tearing it into pieces with the beak. In size they range from 15 to 60 cm (6 to 24 in); the female falcon is larger than the male, as in all diurnal (active during the day) birds of prey. The nesting habits vary; the birds may construct a loosely built nest in a tree, lay eggs on a bare ledge on a rocky cliff, or use a hollow tree or a manufactured nest box. Some species nest in colonies. Female falcons lay four or five eggs, the colour ranging in various species from white to reddish, mottled brown.

Several species of falcons, notably the peregrine, have long been trained as hunting birds (see Falconry). The peregrine is blue-black on the head and back; its underparts are white with light brown stripes.

The largest of the falcons is the gyrfalcon, females of which are about 64 cm (25 in) long. It nests in Arctic regions of both the Americas and Eurasia, and has colour phases ranging from almost pure white to dark grey. A group of 13 falcons called kestrels includes the smallest members of the genus. The common kestrel of Eurasia, which grows up to 34 cm (nearly 14 in) long, can often be seen hovering over motorway verges, searching for voles and other small animal prey. The slightly smaller lesser kestrel lives near the Mediterranean Sea and feeds mainly on insects, which it catches on the wing. Only one species is found in the Americas; this is the American kestrel, formerly called the American sparrow hawk. It ranges in size up to 27 cm (10y in) long. It is common in North America, even inhabiting cities, and feeds principally on insects, but also on small birds, mammals, and reptiles. A slightly larger falcon, the merlin, 31 cm (12 in) long, is found in both Eurasia and North America, where it was formerly called the pigeon hawk. The only other North American species is the appropriately named prairie falcon, a pale brown bird about 50 cm (19y in) long.

Scientific classification: Falcons belong to the family Falconidae of the order Falconiformes. They mainly make up the genus Falco. The peregrine is classified as Falco peregrinus and the gyrfalcon as Falco rusticolus. The common kestrel is classified as Falco tinnunculus, the lesser kestrel as Falco naumanni, the American kestrel as Falco sparverius, the merlin as Falco columbarius, and the prairie falcon as Falco mexicanus.