The hawk is a bird of prey belonging to the falcon family. There are 300 or 400 species of falcons, hawks, and eagles in the world; thirty or more are found in North America. They usually migrate in flocks but, in hunting and nesting, they are solitary birds. The hawk lives chiefly on insects and small mammals, such as field mice and ground squirrels. Bird students insist that few birds are caught by hawks and that their service in keeping fields free from destructive animals is so valuable that, aside from the sparrow hawk, their occasional theft in a poultry yard is not worth mention. They nest usually in trees, though in a prairie country they build in bushes or even on the ground. Eggs, two to six, according to the species. The female is larger, stronger, and bolder than the male. The hawk is swift and silent on the wing, so that its approach is not heard by its prey. The claws are formed for seizing and holding. The hawk strikes with the hinder claw in pouncing and grips with the other so as to hold firmly. When the leg is bent a cord or tendon closes the talons so that they cannot be opened without straightening the leg. When a hawk strikes an ani­mal its settling weight, by bending the legs at the knees, serves to close the talons and clutch the prey. This gives a hawk and all birds of prey a grip such as a person would have if his hand could not be opened or shaken off so long as his arm were bent at the elbow. The bill is also strong and well adapted to tear flesh apart.
   Among the hawks most often seen several deserve mention. The fish hawk or Ameri­can osprey lives almost wholly on fish which it catches by darting from the wing. It nests usually in a tree in a swamp. The swallow-tailed hawk or kite, black above and white beneath, with long pinions and a forked tail, is ever on the wing. The snail hawk of Florida dives into shallow water for a snail, then flies to a low perch to enjoy it, picking out the flesh without injuring the shell. The marsh hawk, a gray, ashy bird above, white beneath, with a white patch on its rump, is about twenty inches long. It courses ceaselessly over low grounds and is an exception by way of nesting on the ground. The red-tailed hawk and the red-shouldered hawk are not infrequently called chicken hawks. Of 782 stomachs of chicken hawks examined by the United States Depart­ment of Agriculture, 120 contained poultry or birds ; 390, mice ; 171, other small mammals; 27, snakes; 69, frogs; 141, insects; 16, spiders; 15, crawfish; 3, fish; 1, centipedes; and 103 were empty. Of the duck hawk, the falcon of history, a less favorable report is made. The falcon lives almost entirely on ducks, teal, snipes, and other birds caught near the shore. The pigeon hawk, named from its appearance, lives chiefly on small birds.