1. Environmental Medicine Consortium, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27606, USA
2. Minnesota Department of Natural Resources, Farmland Wildlife Research Center, Madelia, Minnesota 56062, USA
3. Current address: Department of Forestry and Environmental Resources, Fisheries and Wildlife Sciences Program, North Carolina State University, Raleigh, North Carolina 27603, USA
4. Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings, South Dakota 57007, USA
5. Current address: Department of Biology and Wildlife, University of Alaska Fairbanks, 211 Irving 1, Fairbanks, Alaska 99775, USA
6. Current address: Hayden-Wing Associates, Environmental Consultants, PO Box 1689, Laramie, Wyoming 82073, USA
7. Current address: Pennsylvania Game Commission, Ligonier, Pennsylvania 15658, USA