1. Wyoming Cooperative Fish and Wildlife Research Unit Department of Zoology and Physiology University of Wyoming Laramie WY 82071‐3166 USA
2. Department of Fish and Wildlife Washington 111 Sherman Street, La Conner WA 98257 USA
3. U.S. Geological Survey Wyoming Cooperative Fish and Wildlife Research Unit Department of Zoology and Physiology University of Wyoming Laramie WY 82071‐3166 USA