Falco lineatus, Gmel. Syst. Nat. vol. i. p. 268.— Lath. Synops. vol. i. p. 27.— Wils. Amer. Ornith. vol. vi. p. 86. PL 53, fig. 3. Young Male.
Falco hyemalis, Ch. Bonaparte, Synops. of Birds of the United States, p. 33.
Adult Male. Plate LVI. Fig. 1.
Bill short, as broad as deep, the sides convex, the dorsal outline convex from the base; upper mandible cerate, the edges blunt, slightly inflected, with an obtuse lobe towards the curvature, the tip trigonal, deflected, very acute; lower mandible involute at the edges, a little truncate at the end. Nostrils round, lateral, with a soft papilla in the centre. Head rather large. Neck and body rather slender. Legs longish; tarsus rather slender, anteriorly scutellate; toes scutellate above, scaly on the sides, scabrous and tuberculate beneath; middle and outer toe connected at the base by a small membrane; claws roundish, slender, curved, very acute.
Plumage compact, imbricated; feathers of the head and neck narrow towards the tip, of the back broad and rounded; tibial feathers elongated behind. Wings long, third and fourth primaries longest, first short.
Bill light blue at the base, bluish-black at the tip; cere, basal margin of the bill, edges of the eyelids, and the feet, bright yellow. Iris hazel. Claws black. Head, neck, and back, light yellowish-red, longitudinally spotted with dark brown. Tail brownish-black, banded with greyish-white, the tip of the latter colour. Lesser wing-coverts bright yellowish-red, spotted with brown; larger coverts and secondary quills dusky, broadly barred with white; primary quills brownish-black banded with white, the greater part of their inner webs being of the latter colour. Lower parts of the neck and under wing-coverts light yellowish-red, the former longitudinally lined with blackish; breast reddish-white, marked with transverse hastate yellowish-red spots; abdomen and under tail-coverts reddish-white. Tibial feathers yellowish, transversely barred with dull orange.
Length 18 inches; bill along the back 1¼, along the gap from the tip of under mandible 1¼; tarsus 2¾.
Adult Female. Plate LVI. Fig. 1.
The female differs from the male in being a little larger, and in having the tints lighter.