Adult Plumage:
Summer Plumage:
- The summer plumage features a head with a mix of colors. The forehead and eyebrows are white, lightly speckled with brown. The area in front of the eyes and the cheeks are pale white.
- The dorsal (back) coloration varies between rufous (reddish-brown), black, and gray.
- The crown (top of the head) is pale rufous-brown, with broad pale rufous edges on the head feathers.
- The flanks (sides of the body) and the central portion of the upper tail feathers are brown, with white on the sides.
- The ventral (belly) plumage is white, with a dark brown band across the neck and chest. The abdomen has a large black streak.
- The wings are dark brown, with the primary flight feathers having white shafts (the central part of the feather). The wing coverts (smaller feathers covering the base of the flight feathers) have white edges.
- The central tail feathers are dark brown, while the outer tail feathers are gray-brown with broad white edges.
Winter Plumage:
- The winter plumage includes pale gray foreheads and eyebrows.
- The dorsal (back) is gray-brown, with a darker center to each feather.
- The ventral (belly) is white, with the neck and chest tinged with gray and showing a few pale brown streaks.
- The wings are brown with gray edges.
- The central tail feathers are dark brown, and the outer tail feathers are gray-brown with white edges.
- The eyes are dark brown.
- The beak and legs are black.
Measurements:
- Wing: 117 – 130 mm
- Tail: 30 mm
- Leg: 25 – 28 mm
- Beak: 31 – 42 mm
Distribution:
This species is distributed in eastern Siberia, migrating south in winter to Japan, China, Indochina, and North America. In Vietnam, this species is rare and has only been observed during the winter in Thua Thien and Southern Vietnam.