1. Smithsonian Migratory Bird Center, Smithsonian Conservation Biology Institute, Washington, DC, USA
2. Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
3. Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
4. Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA