• Mittlehauser, Glen Howard
  University of Maine Graduate School
  

Harlequin ducks wintering in eastern North America numbered fewer than 1,000 individual in the 1980s and were declining at some sites. In 1990, the population was protected from hunting and listed as endangered by the Committee on the Status of Endangered Wildlife in Canada. Little is known about the winter ecology of this endangered population. I conducted winter surveys of harlequin ducks in Maine from 1988-99 and reviewed records in eastern North America to summarize their number and distribution, and estimate population trends. I estimate approximately 1,800 birds wintered in eastern North America in the late- 1990s. Although this estimate is more than twice the number estimated in the 1980s, additional survey data likely account for much of this increase. Numbers in Atlantic Canada and Maine, which account for -75% of the wintering population, suggest a recover in numbers since 1991, coinciding with closure to hunting. At wintering locations south of Maine, numbers have increased since 1970.