English: Greater Scaup, Bluebill, Broadbill
Russian:  Морская чернеть     
German: Bergente
French: Fuligule milouinan
Mongolian:  Тэнгисийн шумбуур
Japanese: スズガモ (Suzu-gamo)

Body length: 42-51 cm
Wing span:  71-80 cm

Habitat: Breeds in habitats (fjords, archipelagos) on salt or brackish water, or on fresh-water lakes and pools in mountains (birch and willow zones) and tundra. Migratory. Wintering birds gregarious, diving for molluscs on open sea, or are seen along coasts and in bays.

Identification: Medium-sized with rather large, rounded head, and sloping and of body when swimming. ♂ distinctive. Other plumage similar to Tufted Duck, with similar white-bar, but note: no hint of crest on hindcrown; head shape more elongated and profile smoothly rounded; body longer; and less black on tip of bill (mainly just nail black; Tufted has whole tip black). Beware of confusing hybrids, and the possibility of a rare vagrant Lesser Scaup.

• Adult ♂ breeding: Head black with green gloss, eye yellow; breast and stern black; flanks white, back greyish-white (fine vermiculation apparent only at closer range) . Bill pale grey with small, fan-shaped black nail patch. In flight, light back usually obvious, as are white wing-bars; upper fore-edge of wing vermiculated, appearing medium grey (darker than back but not black as on Tufted).
• Adult ♀: Dull brown with pale brown-grey flanks and slightly darker back, latter with some greyish vermiculation (visible at close range only), and striking broad white band surrounding base of bill (Tufted may have some white at bill-base though usually less, and only rarely extending clearly over culmen). In late spring /summer, a prominent pale patch on ear-coverts on most.
• Adult ♂ eclipse: Rather similar to breeding, but with brown cast on head, breast and back, and often a little white around bill-base.
• Juvenile: Resembles adult ♀, but less white at bill-base, slightly darker bill with indistinct darker nail area, and paler flanks. Young ♂ attains most of adult plumage by end of 1st winter, but not fully until 2nd winter.