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BASIS # 2070A7Y11

Title Winter habitat and food of seaducks in Chesapeake Bay and late winter movements of black scoters from the Bay to breeding areas

Project Description In the Chesapeake Bay area, seaducks are typically defined as scoters (black, surf, and white-winged) and oldsquaw. Eiders and harlequin ducks also are seaducks, but because of their low numbers are not typically considered important seaducks of the Bay. Although the common eider is more abundant in New England and the Maritimes, the harlequin duck is very rare and is possibly close to being threatened on the Atlantic coast. The three species of mergansers (common, red-breasted, and hooded), the bufflehead, and the goldeneye (common and Barrow's) are also considered seaducks by the Sea Duck Joint Venture, but often are considered in a separate category for waterfowl surveys of the Chesapeake Bay. On a continental basis there are 15 species that are classified as seaducks (Elliot 1997). Seaducks on the Chesapeake Bay have received more attention in recent years as hunters have increased hunting pressure on these species, mostly due to closed seasons on Canada geese (Perry and Deller 1994). The distribution and abundance of seaducks could be influenced by hunting pressure. Hunting could become a more serious problem in the future for seaducks in combination with the habitat problems in the Bay. Past food habits work conducted by Cottam (1939) and Stewart (1962) on seaducks determined that they were mainly feeding on mollusks in the Bay area. These reports indicated no problems with regard to habitat. Recent concerns about the decline in numbers of seaducks on the Bay, however, have given managers reason to suspect changes in habitat conditions that could be impacting these species. Research is needed in the Chesapeake Bay to determine the present food habits of seaducks and the important habitats for these birds in the Bay. There have been few studies conducted on harlequin ducks and no known food habits analyses conducted on this species in the Atlantic coast area. The location of the breeding and molting areas of some species of seaducks is uncertain and in need of further study (K. McAloney, pers. comm). The black scoter is of special concern, because it is both the least common of the three scoter species and the species least studied (Kehoe 1994). The Eastern Technical Team of the Sea Duck Joint Venture has recommended new research on this species to learn more about its movements to breeding and molting areas. Satellite tracking of black scoters instrumented in late winter on the Chesapeake Bay will provide new information that will be beneficial to protecting critical breeding and molting habitat of this species and improving future management of its populations.

Keywords black scoter, chesapeake bay, ducks, food habits, joint venture, mid winter, satellite, seaduck, surf scoter, surveys, telemetry, transmitter, waterfowl, white-winged scoter

Principal Investigator Matthew Perry, USGS Patuxent Wildlife Research Center: Matt_Perry@usgs.gov

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