"Adult male in winter plumage.--Above uniform olive-brown with a slight gloss of bronzy olive; scapulars and wing-coverts like back, but having a few tiny white spots on the margins; lower back and rump darker, blackish brown with white edges to the feathers; upper tail-coverts pure white; lesser wing-coverts, outer median, and outer greater coverts uniform olive-brown; alula, primary-coverts, and quills blackish brown, secondaries like the back and freckled with tiny white spots on the edges; tail-feathers white, the center ones with three black bars on the terminal half, these bars disappearing gradually on the lateral feathers, outer ones being entirely white; crown, hind neck, and mantle uniform ashy brown; a supra-loral streak of white; lores dusky, surmounted by an indistinct, white eyebrow, lined with blackish streaks; sides of face, ear-coverts, and cheeks white, rather broadly streaked with blackish brown; throat white, streaked with brown on the sides; lower throat, sides of neck, and fore neck also distinctly streaked with brown; remainder of under surface pure white; sides of upper breast brown, slightly mottled with white; under wing-coverts and axillars blackish, barred very plainly with white; lower primary-coverts and inner lining of quills uniform, with white dots along the inner edge of the secondaries. 'Bill dusky above, reddish beneath; feet grayish blue, tinged with green; iris dusky.' (Macgillivray.) Length, 228; culmen, 35; wing, 137; tail, 56; tarsus, 33. "Adult male in breeding plumage.--Differs from the winter plumage in being much more variegated, the whole of the back being spotted with white, the spots being arranged in pairs on the edges of the feathers, which are also tipped with a bar or twin spots of white; the whole of the head and neck streaked with white, and the brown streaks on the side of the face, fore neck, and chest very broad and distinct, the sides of the upper breast being brown, very much mottled with bars of white. Length, 236; culmen, 35; wing, 137; tail, 55; tarsus, 30. "Adult female in breeding plumage.--Does not differ in color from the male, but is not quite so strongly marked. Length, 229; culmen, 38; wing, 142; tail, 50; tarsus, 33. "Young in autumn plumage.--Scarcely differs from the winter plumage of the adult, but, when freshly molted, it has indistinct margins of ashy bronze on the feathers of the upper surface; the tail-bands are narrower on the center feathers, while the subterminal band is broader than in the adults. "The change to the summer plumage is apparently effected by a distinct molt, which takes place while the bird is in its winter quarters, and in many instances, especially in the case of the males, the summer plumage is completely assumed before the species leaves for its breeding place." (Sharpe.) Genus HETERACTITIS Stejneger, 1884. Bill straight, longer than tarsus; back, rump, and tail-coverts uniform in color. 107. HETERACTITIS BREVIPES (Vieillot).