The Swallow-tailed Hawk pairs immediately after its arrival in the Southern States, and as its courtships take place on the wing, its motions are then more beautiful than ever. The nest is usually placed on the top branches of the tallest oak or pine tree, situated on the margin of a stream or pond. It resembles that of the Common Crow externally, being formed of dry sticks, intermixed with Spanish moss, and is lined with coarse grasses and a few feathers. The eggs are from four to six, of a greenish-white colour, with a few irregular blotches of dark brown at the larger end. The male and the female sit alternately, the one feeding the other. The young are at first covered with buff-coloured down. Their next covering exhibits the pure white and black of the old birds, but without any of the glossy purplish tints of the latter. The tail, which at first is but slightly forked, becomes more so in a few weeks, and at the approach of autumn exhibits little difference from that of the adult birds. The plumage is completed the first spring. Only one brood is raised in the season. The species leaves the United States in the beginning of September, moving off in flocks, which are formed immediately after the breeding-season is over.
Hardly any difference as to external appearance exists between the sexes. They never attack birds or quadrupeds of any species, with the view of preying upon them. I never saw one alight on the ground. They secure their prey as they pass closely over it, and in so doing sometimes seem to alight, particularly when securing a snake. The common name of the Snake represented in the plate is the Garter Snake.
Falco furcatus, Linn. Syst. Nat. vol. i. p. 129.—Lath. Ind. Ornith. vol. i. p. 22.—Ch. Bonaparte, Synops. of Birds of the United States, p. 31.
Swallow-tailed Falcon, Lath. Synops. vol. i. p. 60.
Swallow-tailed Hawk, Wils. Amer. Ornith. vol. vi. p. 70. Pl. 51. fig. 2.
Adult Male. Plate LXXII.
Bill short, strong, curved, compressed towards the tip, opening to beneath the eye; upper mandible cerate, its dorsal outline curved from the base, the edges acute and overlapping, the tip trigonal, very acute; lower mandible rounded on the back, the edges acute, the tip rounded and declinate. Head large, neck short, body robust. Feet rather short; tarsus very short, scaly all round; toes scaly, scutellate above, excepting at the base; claws curved, very acute.
Plumage rather compact, blended, glossy. Wings very long and acute, the third quill longest, the first equal to the fifth, the primaries widely graduated, the secondaries comparatively very short. Tail very deeply forked, of twelve feathers, the lateral ones extremely elongated.
Bill bluish-black above, light blue on the cere, and the edges of both mandibles. Edges of the eyelids light blue; iris black. Feet light blue, tinged with green; claws flesh-coloured. The head, the neck all round, and the under parts, are white, tinged with bluish-grey; the shafts of the head, neck, and breast blackish. The rest of the plumage is black, with blue and purple reflections.
Length 25 inches, extent of wings 51½; beak along the back 1¼.