The North American subspecies of White-winged Scoter (Melanitta fusca deglandi) nests on freshwater and brackish lakes in the western boreal forest from Alaska through northwestern Canada's prairies and parklands to east of the Hudson Bay. They winter in large bays and estuaries along the Pacific coast from the Aleutian Islands to southern Baja California and on the Atlantic coast from Newfoundland to Texas. Because scoter species are difficult to distinguish during breeding aerial surveys, counts for the three species of scoters (Black Scoter, Surf Scoter, White-winged Scoter) are, at times, combined; therefore there is no accurate breeding population estimate specific for White-winged Scoters. However, it is believed that the North American population has declined by more than 50% across their breeding range to 500,000 - 800,000 birds. White-winged Scoters are highly susceptible to oil spills because they congregate in high densities on coastal waters, often along oil transportation routes, which could decimate local wintering populations. Other threats include toxic chemicals, drowning in gillnets, sand mining for beach building, interaction with mussel aquaculture, the potential for overharvest, and the decline of food resources from degradation of water quality or overfishing of clams and mussels. Little information exists for their life history and ecology, or links among their breeding, wintering, and molting distributions. Recent studies including satellite telemetry, feeding ecology, and nesting ecology are adding to our knowledge. These studies allow biologists to track the long distance movements of individual birds throughout the year, assess the availability and nutritional quality of food resources, and provide opportunities to collect tissue samples for genetic and contaminant analyses. Efforts are also underway to develop or improve sea duck surveys through testing of alternate survey methods, but due to their overland migration rather than coastal migration route few White-winged scoters are seen on the Atlantic Coast.

Date: September 2010

Sources:
Perry M.C, A. M. Berlin, P. C. Osenton, and C. S. Bond. 2008. Atlantic Seaduck Project, USGS Patuxent Wildlife Research Center, Laurel, MD. Retrieved September 2010 from http://www.pwrc.usgs.gov/resshow/perry/scoters/

Sea Duck Joint Venture. 2010. Sea Duck Joint Venture Implementation Plan for April 2010 through March 2013. Report of the Sea Duck Joint Venture. Available at U.S. Fish and Wildlife Service, Anchorage, Alaska, and Environment Canada, Sackville, New Brunswick. Also available at seaduckjv.org. 26 pp.

Sea Duck Joint Venture. 2003. Sea Duck Joint Venture Sea Duck Information Series for October 2003. White-winged Scoter. Retrieved September 2010 from http://seaduckjv.org/infoseries/wwsc_sppfactsheet.pdf.

Sea Duck Joint Venture. 2003. Sea Duck Joint Venture Species Status Reports for March 2003, White-winged Scoter. Retrieved September 2010 from http://seaduckjv.org/meetseaduck/species_status_summary.pdf. Pgs 59-61.