1. Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
2. U.S. Geological Survey, Tennessee Cooperative Fish and Wildlife Research Unit, Cookeville, TN 38505, USA
3. U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA (retired)
4. Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA