Seasonal Movement of Pacific Common Eiders Breeding in Arctic Canada

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Pacific Common Eiders (Somateria mollissima v-nigrum) were tagged with satellite transmitters at a site in central arctic Canada, and their year-round movement was tracked to determine migration routes, timing of movement, and location of moulting, wintering and staging areas. Males departed the nesting colony in the second week of July about a week after median date of start of incubation. Two thirds of the males remained in arctic Canada to moult, primarily in outer Bathurst Inlet, Dolphin and Union Strait and off Cape Parry, while the rest moulted closer to the wintering area, mostly at Kolyuchin Bay in northern Russia. Females remained on the nesting colony until time of hatch, and then moved to marine waters within 45 km of the colony to moult. Males that moulted in Canada departed on fall migration in early October, whereas females departed approximately two weeks later. Fall migration through the Beaufort and Chukchi seas took an average (± SD) of 11 ± 4 days, and none of the eiders staged until they reached the Chukotsk Peninsula in the northern Bering Sea. All but one eider wintered in the polynyas and flaw leads off the southeast coast of Chukotsk Peninsula and St. Lawrence Island; the exception likely wintered north of Nunivak Island, Alaska. Spring migration of birds destined for breeding areas in North America lasted 2.4 ± 0.7 months. Four key spring staging areas were identified: off Chukotsk Peninsula just north of the wintering area, eastern Chukchi Sea, southeast Beaufort Sea, and Lambert Channel in Dolphin and Union Strait. Eiders arrived on their breeding grounds in mid-June. All females returned to within 2 km of the nest site used the previous year (n = 7). By contrast, males were widely distributed across the breeding range in the second year from northeastern Russia to central arctic Canada. Assuming a male follows a female to her breeding area, the dispersal of males in the second breeding season suggests that Pacific Common Eiders from across eastern arctic Russia, northern Alaska and western arctic Canada are all part of the same population that winters in the northern Bering Sea. All females (n = 4), plus those males that returned to Canada to breed in the second year (n = 3), moulted within 24 km of the moult site used the previous year. However, two males that bred in Russia in the second year remained in Russia to moult, thus using an entirely different area. All wintered in the same general location in two consecutive years (n = 5). Due to their tendency to congregate in large numbers in a few select locations, especially during spring migration and winter, Pacific Common Eiders are vulnerable to changes in their environment such as oil spills and altered ice conditions brought about by climate change.

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  • Author: Environment Canada
  • Language of Document: Separate English/French
  • Document Type: Report
  • Cat. No.: CW69-5/521E
  • ISBN: 978-1-100-20238-9
  • Size: 21.6x28 cm
  • Pages: 68
  • Year: 2012
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