Adult Plumage Description
Summer Plumage:
The dorsal surface is dark brown with pale white tips on the feathers; many feathers have two white streaks near the tip, especially on the shoulders. The flanks are gray, with white feather tips. The white tail has vertical and horizontal black markings. The tail feathers are gray. The belly, neck, sides of the head, and throat are rufous. The posterior belly is white, and the undertail coverts have narrow black markings. The wing coverts are pale brown, and the greater wing coverts have white tips. The primary wing coverts are dark brown with black feather tips and white feather shafts. The secondary wing feathers are pale brown with white tips, and the inner vanes are pale.
Winter Plumage:
The dorsal surface is gray with narrow dark streaks along the feather shafts. The wings and upper tail are similar to the summer plumage. The sides of the head, throat, and entire belly are white with few pale brown markings on the sides of the head, chest, and flanks. The eyes are brown. The beak is black. The legs are brownish-yellow.
Measurements:
Wing: 142 – 152 mm; Tail: 64 mm; Tarsus: 31 mm; Bill: 31 mm.
Distribution:
This species nests in Siberia and North America; it migrates south in winter, reaching as far as Australia and Spain.
Occurrence in Vietnam:
This species has been recorded on the coast of Thừa Thiên, Vietnam.