Greater Scaup

识别特征

The adult greater scaup is 39–56 cm (15–22 in) long with a 71–84 cm (28–33 in) wingspan and a body mass of 726–1,360 g (1.601–2.998 lb). It has a blue bill and yellow eyes and is 20% heavier and 10% longer than the closely related lesser scaup. The male has a dark head with a green sheen, a black breast, a light back, a black tail, and a white underside. The drake or male greater scaup is larger and has a more rounded head than the female. The drake's belly and flanks are a bright white. Its neck, breast, and tail feathers are a glossy black, while its lower flanks are vermiculated gray. The upper wing has a white stripe starting as the speculum and extending along the flight feathers to the wingtip. Legs and feet of both sexes are gray. <p>The adult female has a brown body and head, with white wing markings similar to those of the male but slightly duller. It has a white band and brown oval shaped patches at the base of the bill, which is a slightly duller shade of blue than the drake's. Juvenile greater scaup look similar to adult females. The greater scaup drake's eclipse plumage looks similar to its breeding plumage, except the pale parts of the plumage are a buffy gray. <p>Distinguishing greater from lesser scaups can be difficult in the field. The head of the greater tends to be more rounded, and the white wing stripe is more extensive. The bill is also tends to be larger and wider, often with a large black nail at the tip. The North American subspecies nearctica typically has a higher forehead and reduced white on the wings, intermediate between the European marila and Lesser Scaup.

分类信息

The greater scaup was formally described by Carl Linnaeus in 1761 under the binomial name Anas marila. The type locality is Lapland. The species is now placed in the genus Aythya that was introduced for the greater scaup by the German zoologist Friedrich Boie in 1822.<p>The genus name Aythya is derived from the Ancient Greek aithuia which refers to a seabird mentioned by Aristotle and others and is thought to refer to a duck, auklet or other seabird. The species name marila is from the Greek word for charcoal embers or coal dust.<p>At least two subspecies of Greater scaup are recognized. The nominate A. m. marila is found from northern Europe to east Siberia, west of the Lena river. The birds in North America are considered a separate subspecies A. m. nearctica, and are distinguishable from those in Europe by a typically higher forehead, and the male having stronger vermiculations on the mantle and scapulars. Additionally, there is less extensive white on the primary feathers than marila. Greater Scaup of East Asia (east of the Lena River towards the Bering Sea) are intermediate between the two subspecies and sometimes lumped with either race or a distinct subspecies A. m. mariloides, though the latter name has been deemed invalid as it was first used to describe the Lesser Scaup A. affinis. Based on size differences, a Pleistocene paleosubspecies, Aythya marila asphaltica, has also been described by Serebrovskij in 1941 from fossils recovered at Binagady, Azerbaijan. The greater scaup's name may come from "scalp", a Scottish and Northern English word for a shellfish bed, or from the duck's mating call: "scaup scaup".<p>A phylogenetic analysis of the diving ducks, examining the skeletal anatomy and skin, found that the greater and lesser scaups are each other's closest relatives, with the tufted duck as the next closest relative of the pair.

学名

Aythya marila

命名信息

(Linnaeus, 1761)

目

Anseriformes

科

Anatidae

属

Aythya

分布与栖息地

The greater scaup has a circumpolar distribution, breeding within the Arctic Circle both in the Old World (the Palearctic) and in North America (the Nearctic). It spends the summer months in Alaska, Siberia, and the northern parts of Europe. It is also found in Asia and is present in the Aleutian Islands year round. The summer habitat is marshy lowland tundra and islands in fresh water lakes. In the fall, greater scaup populations start their migration south for the winter. They winter along the Pacific and Atlantic coasts of North America, the coasts of northwest Europe, the Caspian Sea, the Black Sea, the coast of Japan, Yellow Sea and East China Sea. During the winter months, they are found in coastal bays, estuaries, and sometimes inland lakes, such as the lakes of Central Europe and the Great Lakes.<p>In Europe, the greater scaup breeds in Iceland, the northern coasts of the Scandinavian peninsula, including much of the northern parts of the Baltic Sea, the higher mountains of Scandinavia and the areas close to the Arctic Sea in Russia. These birds spend the winters in the British Isles, western Norway, the southern tip of Sweden, the coast from Brittany to Poland, including all of Denmark, the Alps, the eastern Adriatic Sea, the northern and western Black sea and the southwestern Caspian Sea.<p>In North America, the greater scaup summers in Newfoundland and Labrador, Ungava Bay, Hudson Bay, Lake Winnipeg, northern Yukon, northern Manitoba, and northern Saskatchewan. It winters along the coasts of North America from northern British Columbia south to the Baja Peninsula and from Nova Scotia and New Brunswick south to Florida, as well as the shores of the Great Lakes and the Gulf of Mexico.

繁殖区

NA, PAL : subarctic Iceland and Scandinavia to Kamchatka and the Commander Is. (se Russia); Alaska to n Quebec

非繁殖区

to coasts of nw, ec Europe (e North Atlantic); Black and Caspian seas; Japan and Korean Pen. to e China and Taiwan (w North Pacific); c California (e North Pacific), Great Lakes, North Carolina (w North Atlantic)

迁徙

Complete migrants

行为

Migration pattern: Complete migrants.

保护状况

Population trend: declining.

种群趋势

declining