1. Program in Ecology, Evolution, and Conservation Biology University of Nevada, Reno Reno Nevada 89557 USA
2. Department of Natural Resources and Environmental Science University of Nevada, Reno Reno Nevada 89557 USA
3. Swiss Ornithological Institute Sempach 6204 Switzerland
4. Department of Fish and Wildlife Conservation Virginia Tech University Blacksburg Virginia 24060 USA
5. Institute of Arctic Biology and Department of Biology and Wildlife University of Alaska Fairbanks Fairbanks Alaska 99709 USA