1. Acopian Center for Conservation Learning, Hawk Mountain Sanctuary Association, Orwigsburg, PA, USA
2. Department of Biological Sciences, East Stroudsburg University, East Stroudsburg, PA, USA
3. HawkWatch International, Salt Lake City, UT, USA
4. Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
5. Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, USA
6. Blandon, PA, USA