Eideres, What You Didn’t Know About These Birds

Somateria are a genus of anseriform birds of the family Anatidae known as eideres. The genus Somateria includes three species: Somateria mollissima, Somateria fischeri and Somateria spectabilis and you can learn more about them in this article

Somateria Mollissima – Common Eider

Family: Anatidae – Anatidae


The largest duck in Finland, common eider ducks are robust sea ducks, as large as a small goose. Their head is large and wedge-shaped, their neck is thick. The male is mostly black and white, the female marbled brown.

They are large birds with massive forms, stocky body, triangular head and forehead that run away in the extension of the beak. Two very distinctive characters deserve attention: First, the very marked but not so exceptional sexual dimorphism in anatidae.(See Article: Mallard Duck)

Near Threatened

In Finland, these eiders are classified as “near threatened”, but hunting is still allowed (in 2009, 4 300 eiders were culled). Finland is home to about a quarter of the European Union’s breeding population.

In its nuptial livery, the male eider can be recognized from afar by its whitish back and underparts, tail and dark wing feathers. His cap is black, with green spots on the neck and a whitish breast tinged with pink. The male displays his nuptial livery in June and exhibits his autumn plumage, a fairly uniform dark brown with a broad indistinct eye band and a large white wing patch.

Juvenile eiders in their second summer resemble adult males in their winter plumage, but their breasts are lighter and they do not exhibit a large white wing patch. Females and juveniles are uniformly streaked brown. The mirror wing coverts are brown with a slightly violet tinge, with white wing bands on both sides. Juvenile eiders are dark brown in autumn.

Their eye stripes and other markings are less characteristic. Female and juvenile eiders are distinguished from other species primarily by the long tufts of brown feathers on the sides of their bill that extend into their nostrils. The eider’s legs are greenish yellow (males) or greenish gray (females). Its bill is greenish and its iris is brown.


We do not know everything about its behavioral habits because it is the most secretive of eiders. It is sociable but the troops it forms are less important than those of the other species. On breeding sites, it behaves like a duck on the surface. On the ground, it adopts a particularly awkward rhythm.


During the breeding season, its main diet is composed of insects and, to a lesser extent, mollusks, crustaceans and aquatic plants. In winter, in the open sea, it feeds on clams and other mollusks, which it may forage at great depths. (See Article: Dabbling Duck)


The formation of pairs certainly takes place at the end of winter. In fact, spectacled eiders arriving at nesting sites in May and June are already paired. They nest in isolated pairs but also in loose colonies, often near other anatidae (especially geese and swans).

The nest building period is consistent with that of ice melt. The female may restore an old nest or undertake a new ball-shaped construction that she adorns with available plants and down. At the beginning of incubation or shortly before spawning the males leave the females and initiate a molt migration to the Bering Sea.

The egg size is usually 4 to 5 eggs and the female broods alone for 24 days. If the brood is destroyed early in the season by foxes, mink, skuas and gulls are the usual nest predators, the female may make a young substitution.

They nest early and are able to feed a day or two after hatching, but the mothers continue to monitor and assist them for another four weeks until they are fully self-sufficient. Females are believed to leave the breeding sites with young able to fly and move offshore.

They are placed on the ground, sometimes partially hidden by rocks or vegetation and arranged downdark. Once three to six eggs are laid, the males take leave of the females and incubate for 22 to 24 days and take care of the education of the young. They return to the ocean where they settle in large bands. First-year ducks do not breed and park in salt water until they reach sexual maturity.


Breeds on the Arctic coast in northeastern Russia and Siberia. Sometimes seen in Finland during migration. Nests in tundra, where it is usually associated with aquatic environments, however, it may be an exception to this rule. During the wintering season, it is found in largely ice-free bays and fjords. Apart from the normal, erratic range it usually finds among them eiders strips down with which they can sometimes hybridize, as is the case in Iceland or elsewhere. (See Article: Crested Duck)


Can be seen in Finland at any time of the year, but most often in April-May. Winters mainly in the Barents Sea off northern Norway at Novaya Zemlya. Large bands, often consisting only of males or females, travel in long lines following the coast.

In northern Europe, the migration route is relatively short. The birds leave their nesting sites in New Zealand, the Franz Josef Archipelago or western Siberia to reach the coast from the Barentz Sea to the fjords along the Norwegian Sea.


Crustaceans, mollusks, echinoderms. However, they diversify their menu with small fishes, crustaceans, squids, clypetres and sea urchins. To capture their prey, they are excellent divers and can dive to depths of up to several dozen meters. During the nesting season, given their predominantly terrestrial habitat, their diet varies considerably and insects are an important part of their diet. In winter, it is not as exclusively carnivorous as is often claimed: seaweed and marine plant matter may be an important part of its diet.


During breeding, male gray-headed eideres are mostly white on the front with a dark back. An oval white spot appears on the top of its black wings, and another on its underside on the back of the legs. Two small black triangular veil-like elements emerge from its back. Its head has pearl-gray patterns on the neck and cap.

The top of its bill has a light orange faceplate with black edges. Its small dark red bill with a white tip and fluffy neck feathers give the head a square shape. Its cheeks have green markings and its breast is pale pink. After the breeding season, males molt in the summer to darken and the orange patches on their bills become narrower.

Females and young eiders with gray heads have a fairly uniform marbled brown color. They are distinguished from common eiders by their smaller bills and shorter, less rounded feather coverts on the bill side. Females and juveniles have a greenish-gray bill whose edges give them an apparently smiling expression. Males have orange legs, while females have greenish legs. The iris of the gray eider is yellow.(See Article: Mandarin Duck)

Eider Range

Eiders breed along most of the northern coast of North America, south to Maine in the east and to the Alaskan Peninsula in the west. In winter, the different races move southward, including to Florida on the east coast and to the Washington State coast in the Pacific. However, most Atlantic Coast Eiders winter in Newfoundland, Maine. Most Pacific Eiders winter in Alaska in the Aleutian Islands.

They adopt a wide range of migratory behaviors. Most individuals migrate in spring and fall, some travel long distances, others make short trips, some populations remain in the same region throughout the year.

The spring-migrating common duck moves quickly. Most birds follow the coast, although some individuals have been known to cross large tracts of land, such as the border region of Nova Scotia and New Brunswick or the isthmus of the Avalon Peninsula on the island of Newfoundland. They move in compact troops of a few birds or thousands of birds, flying low over the water at a speed of 60 to 70 kilometers per hour.

In autumn and winter, Eiders migrate without haste. During this migration, they rarely fly over land, usually crossing only prominent points of land or headlands, and only under certain weather conditions, such as snowfall or sea winds. Eiders in the interior Gulf of St. Lawrence are an exception. Many of them first head southwest toward the St. Lawrence estuary, just downstream from Quebec City, and then overfly most of Maine.

Riders begin migrating southward in late fall. The timing of migration is largely influenced by freeze-up and pack ice formation. Both phenomena occur later and later as we move southward and their influence is greater in the northwest Atlantic than elsewhere. In general, one group of birds replaces another: birds from the north replace those that have already bred and migrated south.

In June and July, males and non-breeding birds, replacing their old worn feathers with new ones, migrate to an area where they will be protected from bad weather and predators.They often travel several hundred kilometers north of their breeding grounds. During molt, eiders cannot fly for three to four weeks and lose weight because their energy is used to grow new feathers.

In mid-September, the males fly again and are ready to return to the wintering grounds. However, they move separately from the females and young, and often arrive on the wintering grounds after these two groups, although adult females molt later than they do in August and September.

Eider conservation

The main predators of Common Eiders are large gulls, crows and tillers, which attack eggs and pubescent chicks. Because it nests mainly on small islands, the Common Eider is preyed upon by few mammals. Sometimes arctic foxes or red foxes may kill some eiders; if polar bears enter a breeding colony, they may destroy all nests and kill many breeding females. Common eiders also suffer from starvation in years of food shortage. Female brooders, which do not leave their nests, may also starve during the incubation period.

Hunting has caused significant losses. Prior to the adoption of hunting regulations, the number of breeding common jays had declined considerably, to the point that they had disappeared locally in widely dispersed nesting areas. Fortunately, this bird reacts well to adequate protection. Not only does it reoccupy the areas where it had disappeared, but, in recent decades, it has expanded its breeding range to Western Europe, the British Isles, Atlantic Canada and elsewhere.

In eastern North America, these recoveries began shortly after the Canada-U.S. Migratory Bird Convention came into force in 1916. This limited the hunting of migratory birds. The Common Eider was particularly recognized at that time because of the sharp decline in spawning populations along the east coast.

In most regions, Eiders have recovered dramatically, at a rate of up to 12 per cent. 100 per year; for example, in Maine, the number of nests has increased from fewer than 100 in a single colony in 1910 to more than 20,000 in more than 75 colonies in 1970. Scientists do not know how many common ducks currently live in Canada.

In southern Newfoundland, breeding populations have yet to recover. This is due, in part, to the fact that prior to 1949, the year Newfoundland joined Confederation, these regions were not subject to the provisions of the Migratory Bird Convention Act. In addition, there was a lack of public awareness and enforcement of hunting regulations under the Act. Illegal hunting and egg collection in spring and early autumn, when the local breeding population is present, have prevented an increase in the number of local breeders.

Another area of concern is the harvest of the wintering northern race (S. m. borealis) in southwest Greenland, which breeds in the eastern Canadian Arctic and western Greenland. It is estimated that this harvest may not be sustainable and the population may decline.

In addition, the Pacific race (S. m. v-nigra) has experienced considerable declines since the 1980s for unknown reasons.

In Canada, sport hunting of ducks is permitted during a winter hunting season, including in Newfoundland and southern Labrador. This is because the Eiders found off the coasts of Newfoundland and Labrador and in the Gulf of St. Lawrence during the winter are not local nesters: they belong to large breeding populations in the Arctic.

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