Adult Male:
Summer Plumage: Forehead and crown pale yellowish-brown. Remainder of the head and neck pale reddish-brown. Around the tail and on the shortest upper tail coverts, barred with black and white, with more white on the flanks and upper tail coverts. The longest tail feathers are black. The central tail feathers are pale brownish-black, this color gradually transitioning to the lateral tail feathers, with white tips on the outermost tail feathers. The lesser wing coverts are pale grayish-brown with white speckling. Other coverts are white. Primary feathers are brown with pale shafts, except for the tips. Secondary feathers are steel-green with black edges and tips. The outer webs of the last secondary feathers are white with black borders. Tertials are black with white edges, inner webs pale gray. Upper breast reddish-purple. Undertail coverts black. The remaining ventral surface is white. Winter Plumage: Similar to the female, but with white wing coverts.
Female:
Head and neck reddish, slightly tinged with gray and with dark brown spots. Back brown, with each feather edged with a lighter color, in some places almost white. Wings like the male, but the lesser wing coverts are pale grayish-brown, the speculum less glossy, sometimes without iridescence.
Juveniles:
Plumage similar to the female but slightly smaller in size. Eyes brown or reddish-brown. The female’s eyes are paler. Bill bluish-gray, with a black tip. Legs grayish-green.
Measurements:
- Wing (male): 255 – 270 mm, (female): 232 – 268 mm;
- Tail: 95 – 110 mm;
- Tarsus: 35 – 40 mm;
- Bill: 31 – 35 mm.
- Weight (male): 0.65 – 0.80 kg, (female): 0.53 – 0.77 kg.
Distribution:
This duck species nests in Europe and Asia, from Iceland and Scandinavia to Mongolia. In winter, they migrate to Africa, India, southern China, and Indochina.
Vietnam: This species is quite common in the Northern Delta from November to January and in the Central region from December to March.