1. Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and PhysiologyUniversity of Wyoming, Department 3166, 1000 E. University AvenueLaramie WY 82071 USA
2. U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and PhysiologyUniversity of Wyoming, Department 3166, 1000 E. University AvenueLaramie WY 82071 USA
3. Department of Zoology and PhysiologyUniversity of Wyoming, Department 3166, 1000 E. University AvenueLaramie WY 82071 USA
4. Wyoming Game and Fish Department 2820 Highway 120 Cody WY 82414 USA
5. Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and PhysiologyUniversity of Wyoming, 804 East FremontLaramie WY 82072 USA