王绒鸭种

特征

王绒鸭体重约1616.71克，翼长约266.3毫米，嘴峰长约33.8毫米，喙宽度约17.5毫米，喙厚度约14.1毫米，跗跖长约42.8毫米，尾长约76.2毫米。王绒鸭是候鸟，其栖息在开放的海洋及海岛环境中，食性为肉食性，主要食物来源是水生动物。

分布

欧亚大陆和北美洲的北极地区。

The king eider (pronounced) (Somateria spectabilis) is a large sea duck that breeds along Northern Hemisphere Arctic coasts of northeast Europe, North America and Asia. The birds spend most of the year in coastal marine ecosystems at high latitudes, and migrate to Arctic tundra to breed in June and July. They lay four to seven eggs in a scrape on the ground lined with grass and down.

Taxonomy and etymology

When he first described the king eider in 1758, in the 10th edition of his opus Systema Naturae, Carl Linnaeus assigned it to the genus Anas, along with the rest of the ducks. In 1819, William Elford Leach moved it and the other large eiders to the genus Somateria, where it has remained since. It is very closely related to the other members of its genus, and is known to hybridise with the common eider. Despite its very large range, it is monotypic.

The genus name Somateria is a combination of the Greek words sōma, meaning "body", and erion, meaning "wool"; the combination (i.e. "wooly body") is a reference to the eider's famously thick, soft down. The specific name spectabilis is Latin for "showy", "remarkable" or "worth seeing", a reference to the handsomeness of the adult male's plumage. The bird's common name, king eider, is a direct translation of its Icelandic name.

Description

The king eider is a large sea duck, measuring 50–70 cm (20–28 in) in length with a wingspan of 86–102 cm (34–40 in). Males are, on average, heavier than females, with a mean weight of 1.668 kg (3.68 lb) for males and 1.567 kg (3.45 lb) for females. An individual bird's mass can vary considerably from season to season—from as little as 0.9 kg (2.0 lb) to as much as 2.2 kg (4.9 lb). Like all eiders, the species is sexually dimorphic; the male is slightly larger and, in breeding plumage, much more colourful than the female. The male is unmistakable with its mostly black body, buff-tinged white breast and multicoloured head. The head, nape and neck are a pale bluish grey. The cheek is pale green. The bill, separated from the face by a thin black line, is red with a white nail and a large, distinctive yellow knob. Some tertials are curved up and form "spurs" along the back.

Habitat and range

The king eider is circumpolar, found throughout the Arctic. It breeds on the Arctic coast of Alaska, Canada, Greenland, Svalbard and Russia, using a variety of tundra habitats. It winters in arctic and subarctic marine areas, most notably in the Bering Sea, the west coast of Greenland, eastern Canada and northern Norway. Wintering birds can form large flocks on suitable coastal waters, with some flocks exceeding 100,000 birds. It also occurs annually off the northeastern United States, Scotland and Kamchatka.

Behaviour

Food and feeding

The king eider's foraging strategies change depending on the season. For much of the year, it is at sea; there, it dives for benthic invertebrates. During the breeding season, it does more of its foraging on freshwater lakes and ponds, where it dabbles, feeding primarily on small invertebrates plucked from the surface of the water. It feeds on mollusks, crustaceans like king crabs, and on sea urchins, starfish and sea anemones.

Breeding

The female builds a scrape nest on the ground, usually near water. She lines it with vegetation and down feathers from her own body. She lays a clutch of 2–7 eggs, which she alone incubates for 22 to 23 days. The young are raised collectively by the females.

Voice

The male's song is a quavering, dove-like cooing, transcribed as croo-croo-croo or hoo-hoo-hooo. The female makes a variety of low clucks, grunts and growls.

Conservation and threats

Due to its large population and vast range, the king eider is listed as a species of least concern by the International Union for Conservation of Nature. The king eider is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.

As eggs and young, king eiders have many predators, including glaucous gull, common raven, parasitic jaeger and Arctic fox.

Traditional uses

The king eider, or qengallek (pronounced [qə.ˈŋaː.ɬək]) in Yup'ik, is a regular source of fresh meat in the spring. They begin their migration past the Yukon–Kuskokwim Delta in late April and are hunted in great numbers. In May, several hundred thousand king eiders pass Point Barrow in northern Alaska on their way to Alaskan and Canadian breeding grounds.