Acknowledgements
This work was supported by ARCS Foundation of Illinois, American Ornithological Society, the Women’s Board of The Field Museum, James Bond Fund, and National Geographic (#WW231R-17). USFWS MI Ecological Services Field Office supported tower construction in Michigan. We thank USFWS, USFS, USDA Wildlife Services, and MI DNR for hosting towers and A. Makarewicz and the Davies and Sansote families for providing field housing in Michigan. We also thank Josie, M. Seymour, and F. Wolff for hosting towers and M. Tukeva and the Campaignes for providing field housing on Cat Island. Finally, we thank N. Gottel, C. Moreau, T. Price, M. Ramalho, J. Novembre, B. Trevelline, E. Videvall, and B. Weigel for advice on this study as well as the many field technicians who helped collect samples.