Their migration routes have been charted. Their breeding biology is known. Their eggs meat and feathers have long been used by man. But eiders at sea remain an enigma.
Nesting in colonies that can number hundreds of birds, the eiders are among the most conspicuous of tundra-breeding birds. Although female eiders are a study in grays and browns that match the arctic tundra, the males are most boldly patterned in black and white, with striking green head colors. When the nesting season ends, the birds disperse over the vastnesses of the northern oceans, out of range of most human observers. Of the four species of eiders, the two most abundant and largest have circumpolar breeding distributions and extensive marine wintering ranges. These are the common eider, Somateria mollissima, and the king cider. S. spectabilis, whose flesh eggs and feathers have played a role in the survival of high-latitude human populations for thousands of years, and whose down has insulating qualities that are yet to be matched by artificially manufactured substitutes. The other two eider species are smaller and have much more restricted breeding distributions that center on the Bering Sea. These are the spectacled eider. S. fischeri, named for the gogglelike feathering pattern around its eyes, and the Steller's eider, Polysticta stelleri, named in honor of G. W. Steller, the naturalist on Bering's ill-fated expedition to Alaska.
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