Canvasback Status and Habitat and Management;Rept. for 1 Jul 84-30 Jun 04

摘要

Large, shallow lakes in south and east central Wisconsin historically provided important migrational staging habitat for canvasback ducks. Canvasbacks are drawn to these lakes and others with large littoral zones that support abundant submerged macrophyte communities, especially those dominated by wild-celery or sago pondweed, and/or macrobenthos communities, especially those dominated by snails and small clams. Large lakes also can provide refuge areas from boating disturbance. The most significant lakes in Wisconsin included Koshkonong, Puckaway, and the Upper Winnebago Pool Lakes (UWPL) of Poygan, Winneconne, and Butte des Morts. However, these lakes attracted few canvasbacks by the early 1970s, and wildlife professionals had insufficient information explaining this decline. In the early 1980s the U.S. Fish and Wildlife Service (FWS) classified the can- vasback as a priority species and called for increased research to better manage the species. FWS considered loss and degradation of staging habitat one of the most urgent problems needing attention.