HAWK, any diurnal bird of prey not an eagle or a vulture. As the general characteristics of this group have been given under Falconidæ, and the use of falcons in sport under Falconry, the general term “hawk” will be treated from the point of view of economic relations. Hawks are found in all parts of the world and number about 450 species. All are of moderate size, and some Old World species are no larger than a robin. All seek their prey by daylight and are endowed with great swiftness of flight, immense clutching power in their talons, hooked and toothed beaks adapted to cutting and tearing flesh and remarkable keenness of vision. (See Eyesight of Animals). All are exclusively carnivorous and rarely taste anything they have not themselves killed. Hawks show great boldness in attacking quarry, seeking it as a rule by patiently watching from an elevated perch until a prospective victim appears, then pouncing on it; but some search for food in suitable places, flying to and fro in the hope of catching sight of a moving animal, or of scaring one from its hiding-place. When it has been caught by a rapid swoop it is borne away in the talons to be eaten at leisure, or carried to the nestlings.

Most hawks are dressed plainly in browns and whites, with darker markings, although some have bright feathers in their plumage, but none has in either sex ornamental crests or plumes. The sexes always differ in size, the female being the larger, often conspicuously so; and the plumage of the young varies much from that of the adults. They nest in forest trees, on rock-ledges or on the ground, and usually lay four or five whitish eggs, heavily blotched with brown, red and lavender. A few, as, for example, the duck-hawk (peregrine), and the fish-hawk (q.v.) (osprey), repair and use the same nest many years in succession, but most species get a new mate and make a new nest every season. The voice of most hawks consists of loud screams, and none sings in any proper sense of the word. Hawks, as a rule, are solitary birds, but in the annual migrations (which affect most species) they sometimes travel in considerable flocks. Few are tameable, yet the osprey and the sparrow-hawk are inclined to accept artificial nesting accommodations near houses when made welcome.

North America has hawks of all kinds, including about 34 species north of Mexico, representing the families Falconidæ, Buteonidæ and Pandionidæ. Taking these in systematic order and passing by the southern kites elsewhere described (see Kite), we come to the three species that may properly be termed “hen-hawks,” since to these three alone may commonly be attributed the loss of poultry suffered on farms and in villages.

True Hen-Hawks.— All are small, fierce and powerful, addicted to the capture of birds, wild and tame, although many wild mice and other small mammals, and a few frogs, lizards and insects, are also eaten. The first of them is the sharpshin (Accipiter velox), a summer resident of all North and Central America, and retiring in winter only to the Southern States. It is known as bird-hawk, chicken-hawk, bullet-hawk and sparrow-hawk. Birds constitute nine-tenths of its fare, speaking generally; and it is able to strike down and carry off fully-grown chickens, quails or grouse, as well as small birds, whose only safety is to make a quick dive into some thick bush. The sharpshin may be known by its small size (length 11 to 13.S inches, wing-spread about 15 inches); long tail, square at the end; slender legs and feet and very long toes. In color it is uniformly bluish-gray or slate-colored, dark on the crown; under parts white, heavily barred with reddish-brown, except the throat, which is narrowly streaked; wing-quills blackish; tail with five blackish crossbars and narrowly lipped with white; feet yellow. Immature young, brownish above, streaked white below.

Cooper's hawk; or the blue darter (Accipiter cooperi), is closely similar in color and proportions, but is nearly a third larger, has stouter feet, and the tail is rounded, not square, at the end, and is indistinctly barred. This species does not go far north but from southern Canada southward is one of the most abundant of American hawks, and like the sharpshin it retreats in winter only from the more northern border of its range. It is known to farmers and sportsmen as chicken-hawk, quail-hawk, swift-hawk and darter.

The third bird-killer is the goshawk (Astur atricapillus), which inhabits Canada and northern Europe, where it has always been one of the favorites of falconers. It is much larger than the others, measuring 22 to 24 inches from bill-tip to tail-end; and when adult is bluish above, crown darker, has a broad whitish stripe over the eye, the whole under surface finely marked with gray and white, and the long tail crossed by four narrow dark-brown bars. Immature young are dusky brown, mottled with reddish and buff. This bold northern marauder is variously called blue hen-hawk, blue darter, dove-hawk, etc., but it is rarely seen in the United States except in midwinter.

The three falcons described above are the true “hen-hawks” and are unprotected by law. They, and they alone, are responsible for virtually all the loss of poultry and game-birds. The description of the methods of the sharpshin given by W. B. Barrows in his admirable ‘Birds of Michigan’ (Lansing 1912) will answer for those of the others:

This is the common "chicken-hawk" of the farmers, and probably is responsible for most of the loss of small chickens. The bird has a habit of dashing suddenly among the poultry, picking up a small chicken in its claws, and carrying it away so quickly that it is commonly impossible to kill the robber. It is very likely to return the same day or the next, and to repeat its visits indefinitely until killed. Unlike the buzzard-hawks, the Cooper's and sharpshin seldom wheel aloft on the lookout for food, but fly swiftly and silently from place to place, flapping the wings rapidly for a few seconds and then gliding noiselessly, always alert and watchful, and ever ready to drop like an arrow on some unsuspecting victim.

Two other small falcons, the pigeon-hawk and the sparrow-hawk, catch small birds when their young are in the nest, and need tender food, but the former is so uncommon, and the latter so little addicted to chicken-stealing, that they need not be feared. Both live principally on insects and mice, the beautiful little sparrow-hawk being particularly helpful by its constant pursuit of grasshoppers and crickets. The duck-hawk, or peregrine, is an enemy to game-birds and waterfowl, but is now rare and extremely shy of humanity.

Beneficial Hawks.— The large hawks so often seen in the country sailing above the fields or perched on some tree at the edges of the woods belong to the genera Buteo and Archibuteo, and are known as “buzzard-hawks.” They do not possess the knightly qualities we admire in the falcons, but unfortunately have constantly to answer for the sins of those dashing gentry. Familiar species in the Eastern States and provinces are the red-tailed, the red-shouldered, the broad-winged and the rough-legged buzzard-hawks. The roughleg, so called because feathered down to the toes, is a northern species, visiting the United States only in winter, when it ranges the fields in search of mice; it is entirely harmless and should be rigidly protected by farmers. Another species deserving of special mention because it is everywhere numerous and a valuable ally of the hard-working agriculturist is the marsh-hawk (Circus cyaneus). It is to be seen only in low, open places where, flying slowly and low, and nesting on the ground, it gets great numbers of mice, frogs and grasshoppers, but no birds. No hawk is more harmless or serviceable, especially as a destroyer of field-mice, that worst pest of the farmer, and it should never be killed. It is easily recognized by its low flight, bluish tint and conspicuous white rump.

Most of these big, slow hawks range across the continent in western varieties; and in addition several species belong exclusively to the plains and mountains of the West, while the southwestern border of the United States is entered by several subtropical species some of which range in summer far up the Californian coast. While indignant and undiscriminating farmers and poultrymen are likely to call all or any of these “hen-hawks,” the mischief of which they are guilty in the nesting-season is so small that it is negligible in comparison with the benefit they render all the year round by their destruction of rabbits, ground-squirrels, gophers, field-mice, grasshoppers, crickets and other injurious creatures that cost the farmer and gardener enormous aggregate loss. No poultry will be sacrificed, even to the bold sharpshin and blue darters when it is housed or brush-sheltered and cared for as good poultry ought to be; and it is the height of folly to shoot hawks indiscriminately. Consult Fisher, ‘Hawks and Owls of the United States in their Relation to Agriculture’ (Washington 1893); Forbush, ‘Useful Birds and their Protection’ (Boston 1907); Weed and Dearborn, ‘Birds in their Relation to Man’ (Philadelphia 1903); and general works mentioned under Birds.