1. National Biological Service, National Wildlife Health Center, 6006 Schroeder Road, Madison, Wisconsin 53711, USA
2. Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Drive, Madison, Wisconsin 53706, USA
3. National Biological Service, Northern Prairie Science Center, 8711 37th Street SE, Jamestown, North Dakota 58401, USA
4. Ohio Cooperative Fish and Wildlife Research Unit, Ohio State University, 1735 Neil Avenue, Columbus, Ohio 43210, USA
5. National Biological Service, Upper Mississippi Science Center, P.O. Box 818, La Crosse, Wisconsin 54602, USA
6. Georgia Cooperative Fish and Wildlife Research Unit, School of Forest Resources, University of Georgia, Athens, Georgia 30602, USA
7. Department of Avian Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602, USA