Somateria mollissima

Female common eiders lead their young to water and may be accompanied by nonbreeding females that help protect the chicks. Broods often join to form "creches" of up to many dozens of young. Once formed, a creche tends to stay together throughout the brood rearing period, although some of the adult females attending it may depart.
Photo Credit: Geoffrey A. Hammerson
Somateria mollissima
Common Name: common eider
Animal Guild: Bird
Class > Order > Family: Aves > Anseriformes > Anatidae
What does the species look like? This is a heavy-bodied duck with a relatively short, stout neck and distinctive long triangular (wedge-shaped) bill and head profile. From fall through early summer, adult males have a black crown, greenish rear of head, dark or yellow bill, black underparts, white upperparts and chest, and black tail and area around the tail. From summer to fall, adult males are dark brown to blackish overall, with a pale brown stripe through the eye, brown breast with white flecking, and back feathers white with black edges. Immature males are similar to females but have a white chest. Adult females are dark gray to rusty-brown, with fine black barring that forms lines on the flanks.
Where is the species found?
States & Provinces
AK, MA, MB, MD, ME, MI, NB, NC, NH, NJ, NL, NS, NT, NU, NY, ON, PE, QC, RI, SC, SD, VA, YT
Distribution

Breeding range extends from Alaska across the Arctic to Labrador and Greenland and south to Maine and New Hampshire; from Iceland, the Faroe Islands, Spitsbergen, and Franz Josef Land south to northern British Isles, northern Europe, and southern Scandinavia; and from Wrangel Island and northeastern Siberia south to Kamchatka and the Commander Islands. Winter range in western North America extends from the ice pack south to the Aleutian Islands, Washington, and Oregon. Winter range in in eastern North America is in Hudson and James bays and from Labrador south to Long Island (New York). Winter range in Eurasia extends from the breeding range south to central Europe in the west and Kamchatka in the east.

Nonbreeding habitat includes rocky seacoasts, bays, and estuaries. Rocks, sandbars, and ice are used as resting sites. Most migration is coastal. Nests are on the ground in grass or brush, usually close to salt water, often on an island or rocky headland or along the shore of a pond or lagoon. Nests often but not always are concealed by plants (forest, shrub, or herbaceous), rocks, logs, or driftwood.

General Phenology and Life History Some populations do not migrate, and in other populations migration may be partially facultative, depending on conditions. Spring migration generally begins in March and extends into April for early nesters and to mid-June for arctic nesters. Common eiders commonly nest in loose aggregations or colonies (usually a few dozen pairs, but up to several thousand pairs in some areas). Females commonly deposit eggs in the nests of other females. Nesting in Maine occurs from late April to early July. Nesting in the Beaufort Sea region begins in mid- to late June. Clutch size averages 3-5. Incubation, by the female, lasts 24-30 days. The female does not feed during incubation but relies on endogenous energy reserves. Eggs hatch mainly mid- to late July (sometimes into August) in the region arctic of Alaska and Canada. Young are tended by the female and led to water soon after hatching. Soon they join young of other broods, Young are independent at around 60-75 days. Females rarely renest if the clutch is lost, unless loss occurs during laying or early incubation. During June and July, males depart from breeding areas to molt (immatures and nonbreeding females may also undertake such migrations). Fall migration varies regionally but occurs mainly in October and November, though females and young may begin moving toward wintering areas in late August-early September. By mid-December most wintering populations have peaked in numbers.
Which phenophases should I observe?
Do you see/hear...?
Activity Live individuals
One or more individuals are seen or heard moving about or at rest.
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Feeding or foraging
One or more individuals are seen feeding or foraging. If possible, record the name of the species or substance being eaten or gathered, or describe it in the comments field.

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Calls or song
One or more individuals are heard calling or singing.

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Territorial individuals
One or more individuals are seen or heard defending a territory. This may be indicated by calls or song used as part of a territorial proclamation, chasing of an individual of the same species from a breeding area (but do not confuse this with courtship behavior, which in some species may involve chasing), or calls or displays directed at individuals of the same or a different species to defend a feeding area.

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Reproduction Courtship
A male and female are seen near one another and are engaged in courtship behavior. Do not include male displays in the absence of a female.

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Mating
A male and female are seen coupled in a mating position, usually with the male on top of the female.

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Nest building
One or more adults are seen constructing a nest or carrying nesting material.

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Occupied nest
One or more adults are seen sitting on a nest, entering or leaving a nest site under circumstances indicating its use for nesting (including nest defense behavior), or live eggs or nestlings are seen in a nest.

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Development Downy young
One or more young are seen covered with fluffy down feathers and not yet any smooth contour feathers.

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Partially-fledged young
One or more young are seen with a mix of fluffy down and smooth contour feathers, and often have an unkempt or ragged appearance.

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Fledged young
One or more young are seen covered with smooth contour feathers and no longer any fluffy, natal down feathers. This includes young incapable of sustained flight and young which are still dependent on adults.

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Dead individuals
One or more dead individuals are seen.

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Dead nestlings or fledglings
One ore more dead nestlings or young are seen.

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Method Individuals at a feeding station
One or more individuals are seen visiting a feeder, feeding station, or food placed by a person.

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What do these phenophases look like?

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