1. Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 1000 East University Avenue Laramie WY 82072 USA
2. Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
3. Haub School of Environment and Natural Resources University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
4. Program in Ecology, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 1000 East University Avenue Laramie WY 82071 USA
5. U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 1000 East University Avenue Laramie WY 82072 USA