Friday 28 December 2012

Common eider

Somateria mollissima

Photo by Andreas Trepte (Wikipedia)

Common name:
common eider (en); pato-eider (pt); eider à duvet (fr); eider común (es); eiderente (de)

Taxonomy:
Order Anseriformes
Family Anatidae

Range:
The common eider is found along the coasts of the northern Atlantic, northern pacific and the Arctic Ocean. In the Atlantic the breeding range goes as far south as northern England and Ireland, and Maine in the United States. In the Pacific the breeding range goes as far as southern Alaska. The wintering range goes as far as the coasts of France, Virginia, northern British Columbia and southern Kamchatka, Russia.

Size:
These large ducks are 55-70 cm long and have a wingspan of 90-105 cm. They weigh 0,9-3 kg.

Habitat:
Common eiders nest in rocky shorelines and tundra, particularly in small offshore islands that are free of mammalian predators. They forage on a wide range of coastal habitats including rocky shores, coastal lagoons, fresh water lakes, sandflats and mudflats and can also be found out at sea.

Diet:
They feed by diving into the water, mainly eating marine invertebrates. Their diet includes molluscs such as mussels, clams, scallops, cockles and snails, crabs, sea urchins and starfishes. They sometimes also eat small fishes and fish eggs.

Breeding:
Common eiders are monogamous and form large breeding colonies that can have over 10.000 birds. They breed in June-August. The nest is a scrape in the ground lined with down that the female plucks for her own body, it is often hidden among tall grasses and always located near the sea. The female lays 4-5 light grey eggs, which she incubates alone for 25-28 days. The chicks leave the nest soon after hatching and start foraging on the sea under the protection of the female, they fledge 65-75 days after hatching. Common eiders reach sexual maturity at 2-3 years of age.

Conservation:
IUCN status - LC (Least Concern)
This species has a very large breeding range and a global population is estimated at 3,1-3,8 million individuals. The overall population trend is uncertain, as some populations are decreasing, while others are increasing, stable, or have unknown trends. In North America the population has undergone a small increase over the last 4 decades.

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