The Pacific population of Steller's Eiders primarily breeds in the Siberian Arctic and molts, winters and stages along the Alaska Peninsula and Northern Bristol Bay (Kertell 1991). Spring migration starts in May as birds disperse to breeding grounds; males and failed- and non-breeding females return to Alaskan molting areas in July and August. Successful breeders and hatch year birds likely return to Alaska in October. Known molting and staging areas include Izembek Lagoon, Nelson Lagoon, Seal Islands, and Kuskokwim Shoals. Within these molting and staging estuaries, Steller's Eiders are commonly found in dense flocks that simultaneously dive while foraging. These flocks are regularly observed roosting on sand bars and beaches facilitating transmission of disease among individuals within flocks. For molting birds there is strong evidence of site fidelity to specific molting locations and the sexes are somewhat segregated temporally and spatially during the flightless period as males molt earlier than females (Flint et al. 2000). However, there is no evidence of segregation of breeding populations among molting areas (Dau et al. 2000).

Previous work on virus exposure (not avian influenza) of molting sea-ducks showed substantial variation in prevalence among flocks and locations (Hollmén et al. 2003). Thus, it seems clear that birds within flocks are not independent from the stand point of virus exposure. During the flightless molt, flocks of birds are functionally isolated within lagoons as large areas of unsuitable habitat separate flocks; however, exchange of individuals prior to the molt likely creates a positive correlation in exposure probability within lagoons. Thus, a sampling strategy spread relatively uniformly across the molting range is the most effective sampling strategy for birds molting in clumped distributions.

No. of samples. A total of 800 birds will be sampled using a 2-stage stratified design. The first level of stratification will be at the level of lagoons or molting areas. The second level will consider functionally isolated flocks of flightless eiders within lagoons where possible. Thus, we will sample 50 birds from each of 4 flocks within each lagoon yielding a total of 200 from each of the 4 lagoons.
Sampling locations: Primary locations in order of priority include Nelson Lagoon, Izembek Lagoon, Seal Islands, and Kuskokwim Shoals. Secondary locations, within these lagoons, will be determined based on channel systems and observed flock locations and movement patterns.
Sampling timeframe: Late August through late September.
Sample demographics: After-hatch-year males and females. The sample will be primarily post-breeding males and both failed and non-breeding (likely sub-adult) females.
Methods of capture: Flocks of flightless birds will be herded with boats and driven out of the water into corral traps. This approach has been used to capture >65,000 Steller's Eiders for >20 years.
Other targeted species: None, flocks of eiders rarely mix with other species.
Supplemental sampling: Small numbers of Steller's Eiders can be sampled in conjunction with other ongoing studies. A study of the nesting productivity of Steller's Eiders near Barrow, Alaska finds from 0 to 30 active nests per year. Fecal samples and a small number of cloacal swabs can be obtained in conjunction with this work. Also, several studies of wintering ecology and movements are capturing <30 Steller's Eiders at several different wintering areas. Cloacal swabs will be taken from these live captured birds.

U.S. Fish and Wildlife Service

Izembek NWR (Sampling at Izembek and Nelson Lagoons)

Yukon Delta NWR (sampling at Kuskokwim Shoals)

U.S. Geological Survey

Dau, C. P., P. L. Flint and M. R. Petersen. 2000. Distribution of recoveries of Steller's Eiders banded on the lower Alaska Peninsula, Alaska. Journal of Field Ornithology 71:543-550.

Flint, P. L., M. R. Petersen, C. P. Dau, J. E. Hines, and J. D. Nichols. 2000. Annual survival and site fidelity of Steller's eiders molting along the Alaska Peninsula. Journal of Wildlife Management. 64:261-268.

Hollmén, T. E., J. C. Franson, P. L. Flint, J. B. Grand, R. B. Lanctot, D. E. Docherty, H. M. Wilson. 2003. An Adenovirus Linked to Mortality and Disease in Long-tailed Ducks (Clangula hyemalis) in Alaska. Avian Diseases 47:1434-1440.

Kertell, K. 1991. Disappearance of the Steller's Eider from the Yukon-Kuskokwim Delta, Alaska. Arctic 44:177-187.