1. University of Minnesota; Minnesota Cooperative Fish and Wildlife Research Unit; 200 Hodson Hall, 1980 Folwell Avenue St. Paul Minnesota 55108 USA
2. U.S. Geological Survey; Minnesota Cooperative Fish and Wildlife Research Unit; 200 Hodson Hall, 1980 Folwell Avenue St. Paul Minnesota 55108 USA
3. U.S. Fish and Wildlife Service; Tamarac National Wildlife Refuge; 35704 County Rd. 26 Rochert Minnesota 56578 USA
4. U.S. Fish and Wildlife Service; Migratory Bird Program; 5600 American Blvd. West Bloomington Minnesota 55437 USA