Relation of highly pathogenic avian influenza (H5N1) prevalence to migration patterns of Pacific common eiders nesting in Northwest Alaska

To examine relationships between highly pathogenic avian influenza prevalence and migration patterns of Pacific common eiders (Somateria mollissima v-nigrum) nesting in Northwest Alaska, we marked 25 adult Pacific common eiders (24 females and 1 male) from the Cape Espenberg breeding area (28 June-7 July 2007) with satellite transmitters and sampled individuals for highly pathogenic avian influenza (H5N1). From each captured eider, we also collected whole blood, serum, and breast, head, and flight feathers for genetic, contaminant, and stable isotope analyses. After transmitter deployment, all marked females remained in the vicinity of Cape Espenberg through October 2007, while the single satellite-tagged male left Cape Espenberg by 31 July and embarked on a molt migration along the northern coast of Alaska, arriving at a molting area in western Canada by 20 August, after having traveled in excess of 1,500 km. As of December 2007, all satellite transmitters remained active (i.e., no deaths or equipment failure) and all but 2 females had migrated to wintering locations away from the Seward Peninsula. By 31 December, 13 of the 25 tagged individuals were located along the southern Chukotka Peninsula, Russia (including the single male), 3 near northwestern St. Lawrence Island, Alaska, and 7 along the coast of the Yukon-Kuskokwim Delta. Given a two-year battery life and our current transmission cycle, we hope to obtain locations for one winter (2007/2008), two autumn seasons, and two breeding/molt seasons. Results from the National Wildlife Health Center indicated that no common eiders or long-tailed ducks sampled at Cape Espenberg were positive for H5N1. Continuing movement data from the satellite transmitters deployed at Cape Espenberg will provide information on migration routes, wintering areas, and seasonal movement patterns for common eiders breeding in northwest Alaska and help clarify population structure among breeding aggregations of Pacific common eiders statewide.