1. Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.
2. Centro de Ecología Aplicada del Litoral (CECOAL, CONICET), Corrientes, Argentina.
3. Center for Avian Population Studies, Cornell Lab of Ornithology, Ithaca, NY, USA.
4. Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN, CONICET), Buenos Aires, Argentina.
5. Museu de Zoologia da Universidade de São Paulo, São Paulo, Brazil.
6. Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA.
7. Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, NY, USA.