Madison, Wisconsin: Wisconsin Department of Natural Resources
Summary
Breeding ducks were studied from 1977-81 on the Grand River Marsh Wildlife Area (GRM) and the Grand River Extensive Area (GREA), a 50-mile square block of land surrounding the GRM. The 2,500-mile² study area includes parts of Adams, Columbia, Dodge, Fond du Lac, Green Lake, Marquette, Sauk, Waushara and Winnebago counties in southeastern Wisconsin.