1. Dept of Environmental Science, Policy and Management; Univ. of California; Berkeley CA 94720 USA
2. Wyoming Cooperative Fish and Wildlife Research Unit, Dept of Zoology and Physiology; Univ. of Wyoming; Laramie WY USA
3. Wyoming Game and Fish Dept; Jackson WY USA
4. National Council for Air and Stream Improvement, Forestry and Range Sciences Laboratory; La Grande OR USA
5. National Park Service, Yellowstone National Park; WY USA
6. US Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Dept of Zoology and Physiology; Univ. of Wyoming; Laramie WY USA