1. Minnesota Cooperative Fish and Wildlife Research Unit, Department of Fisheries, Wildlife, and Conservation Biology University of Minnesota 200 Hodson Hall, 1980 Folwell Avenue Saint Paul 55108 MN USA
2. U.S. Geological Survey, Minnesota Cooperative Fish and Wildlife Research Unit, Department of Fisheries, Wildlife, and Conservation Biology University of Minnesota 200 Hodson Hall, 1980 Folwell Avenue Saint Paul 55108 MN USA
3. Agricultural Research Service, U.S. Department of Agriculture University of Minnesota 1991 Upper Buford Circle Saint Paul 55108 MN USA
4. Farmland Wildlife Populations and Research Group Minnesota Department of Natural Resources 35365 800th Avenue Madelia 56062 MN USA