Falcon (Falco), the crowning genus in the family Falconidae, including numerous species which excel even the eagles as birds of prey. They are represented in all parts of the world except the South Sea Islands, and are almost always distinguished by their carnivorous habit, active life, and that evolved hunting talent which has led to the frequent use of not a few forms in the sport of Falconry (q.v.). The beak is short and strong, with a sharp-hooked point and an upper tooth fitting into a depression in the lower half; the claws are strong and sharp, and the outer toe is rather longer than the inner; the lower part of the leg is covered with a net-like pattern of scales; the regions round about the keen eyes are bare; the wings are long and pointed; the tail is also long and rounded. The falcons are pre-eminent for boldness, keen sight, and muscular power. One is said to have traversed the distance between Fontainebleau and Malta, not less than 1350 miles, in 24 hours; and the speed attained when in pursuit of prey has been estimated at 150 miles an hour. They are able to soar to an immense height, and always endeavour to get above the bird they wish to strike. The distinctness of the various falcons is much disputed by experts; the fivefold grouping here followed is that adopted by Professor A. Newton.
(1) The cosmopolitan Peregrine Falcon (F. peregrinus or communis) was formerly a firmly established British species, but, though still persisting in some parts, has suffered enormously from unreasonable persecution. It is a powerful bird, though only about 16 inches long, and is brave and masterly in its hunting. In colour the adult is blackish-brown to grayish-blue above, and whitish, with a reddish shade, beneath. Especially on the lighter under surface are seen the dark bars, which in this and the gyrfalcons are longitudinal before and transverse after the first moult. The female is larger and more powerful than the male, with a slightly longer body, and decidedly longer wings; she is the 'falcon' of the falconers, the male is a 'tiercel,' the more rufous young forms are 'red falcons' or 'red tiercels.' The peregrine preys upon flying birds, such as wood-pigeons, all sorts of grouse, partridges, and plovers, or by the seashore on puffins, auks, and other marine birds. The falconers pit them against herons, and on its own account a falcon has been known to attack an intruding eagle. The cogent argument used against exterminators of falcons is that which may be urged against any disturbance of the balance of nature: that they kill grouse, pheasants, and other game-birds is undoubted, but they naturally tend to weed out the weaker forms, and thus, unless they predominate unduly, do more good than harm. Some even regard the grouse disease as a nemesis of the destruction of the nobler falcons. Peregrines usually live in pairs, and build large nests, generally of sticks and herbage, on very varying sites—sea-cliffs, inland rocks, or even trees. The Australian Peregrine (F. melanogenys) and the North American form (F. anatum) are probably only varieties of the above species.
(2) Next come a number of northern gyr- or jer-falcons, like the preceding, formerly much used in falconry. The Scandinavian Gyrfalcon (F. gyrfalco), which sometimes wanders farther south, and has been seen wild in Britain; the Iclander (F. islandus), which also comes to Britain; the nearly pure white Greenland Falcon (F. candicans), of which the migrating young have been seen in Britain; and the North American Gyrfalcon (F. labradorus) are important forms. In their native haunts they feed on ptarmigan, geese, and other such birds.
(3) Somewhat distinct are the desert falcons, by some authorities distinguished as the 'lanners' (F. lannarius) and 'sakers' (F. sacer) of south-eastern Europe, North Africa, and south-western Asia, both used in falconry.
(4) The Merlin (F. asalon) is a British species, like the peregrine in process of extermination. The male is bluish above and rather ruddy beneath. It is decidedly smaller than the peregrine, and preys upon smaller birds, such as finches, larks, and thrushes; yet so bold is it that it has been known to turn threateningly upon man.
(5) The English Hobby (F. subbuteo), with upright carriage and long wings, is a summer visitor in Britain, an eager enemy of larks, and sometimes even condescending to eat insects. Both of the last species have been used in British falconry. The Kestrel (Tinnunculus) is a nearly allied genus, separately discussed.