"Adult in winter plumage.--Above ashy gray, slightly varied with dusky shaft-streaks; scapulars bronzy brown like inner secondaries; lower back and rump brown, with a subterminal shade of darker brown; upper tail-coverts also dark brown, with longitudinal shaft-streaks of darker brown; wing-coverts brown, with a slight bronzy gloss, shaft-lines darker, and slight indications of paler edges; greater coverts tipped with white, forming a cross-band on the wing; alula, primary-coverts, and quills blackish brown; shafts of the primaries pale whity brown, that of the first outer primary white; alula white with a brown center; all the primaries white at the extreme base; secondaries brown, white at base of inner web, and fringed with white at the ends; long inner secondaries bronzy brown with dusky centers; middle tail-feathers dusky brown, the remainder ashy brown, with white in the center, increasing in extent toward outer feathers, two external ones entirely white; crown ashy brown like back; lores dull brown surmounted by a streak of white, hardly joined to a second streak above the ear-coverts, which forms an indistinct eyebrow; eyelid white; sides of face and ear-coverts ashy brown, streaked with dusky brown; cheeks and throat white, with a few dusky streaks on cheeks and lower throat; fore neck and upper breast light ashy brown; lower breast, abdomen, sides of body, and flanks pure white; thighs brown, white internally; under tail-coverts white; under wing-coverts and axillars white; coverts round the bend of wing dusky brown with whitish edges; lower primary-coverts brown, forming a patch; quills below ashy brown, somewhat lighter along the inner edge. Length, 140; culmen, 15; wing, 96; tail, 46; tarsus, 18; middle toe with claw, 18. "Adult male in breeding plumage.--Only differs from the winter plumage in being more mottled above, the feathers having black centers, and being tinged with rufous, especially on the edges of the feathers; lower throat and chest have some distinct shaft-lines. 'Bill olive-black, lighter olive brownish at base, especially on lower mandible; feet olive-yellow, joints more dusky; iris dark brown.' (Stejneger.) Length, 135; culmen, 19; wing, 94; tail, 46; tarsus, 16; middle toe with claw, 18. "Adult female in breeding plumage.--Similar to the male, and apparently quite as much mottled. Length, 132; culmen, 20; wing, 99; tail, 47; tarsus, 16; middle toe with claw, 18. "Young birds.--These can always be distinguished from the adults in summer or winter plumage by the narrow sandy buff margins to the feathers of the upper surface, and by the ashy fulvous tinge on the fore neck, which is devoid of the dusky streaks seen in the adults. "Nestling.--Covered with golden buff down, spotted with black, and spangled with silvery tips to the down; the black forms a line down the center of back; under surface dull white, tinged with buff on the fore neck." (Sharpe.) Genus HETEROPYGIA Coues, 1861.