1. Department of Biology, Colorado State University, Fort Collins, Colorado, USA
2. Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
3. Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, USA
4. The Nature Conservancy, San Francisco, California, USA
5. Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway