Male Adult:
Summer Plumage: Head, neck, crop, breast, and upper back are black, with an iridescent green sheen on the head and neck. The remaining back and shoulders are light gray with numerous narrow, wavy black bars. The flanks and uppertail coverts are blackish-brown. The belly and sides are white, with narrow bars on the posterior belly. The undertail coverts are black. Primary flight feathers and tail feathers are brown. Outer secondary flight feathers are white with black tips, the inner ones are pale greenish-black, creating a white wing-patch bordered by black on the front and rear.
Winter Plumage: Similar to summer plumage but duller, appearing to be overlaid with a pale brown wash.
Female:
A broad white band surrounds the base of the bill. The remaining head and neck are dark brown, often with a white spot near the ear. The lower neck, upper back, and breast are brownish with a pale reddish tinge. The remaining upperparts, wings, and tail are pale reddish-brown, with pale white markings on the back and shoulders. The belly is pale white, the area around the vent is pale brown, and the sides and undertail coverts are white with brown bars. The wing-patch is white or opaque white.
Juvenile:
Similar to the adult female but without white on the forehead. The sides of the bill and the head are brown.
General:
Eyes yellow. Bill pale bluish-gray. Legs pale bluish-gray with darker joints and pale black webbing.
Measurements:
- Wing (male): 197 – 235 mm;
- (female): 183 – 225 mm;
- Tail: 45 – 63 mm;
- Tarsus: 34 – 38 mm;
- Bill: 40 – 47 mm.
- Weight (male): 0.80 – 1.10 kg;
- (female): 0.75 – 0.90 kg.
Distribution:
The bird is distributed in North America, Northern Europe, and Northern Asia. In winter, it is found in Africa, India, Myanmar, Southern China, and Indochina.