1. USDA Forest Service, Northern Research Station, Amherst, Massachusetts, USA
2. Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA
3. School of Biological Sciences, University of Northern Colorado, Greeley, Colorado, USA
4. Biology Department, Loyola Marymount University, Los Angeles, California, USA
5. Department of Natural Resources, Cornell University, Ithaca, New York, USA
6. School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama, USA
7. Cornell Lab of Ornithology and Department of Natural Resources, Cornell University, Ithaca, New York, USA
8. Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa, USA