1. Department of Ecology and Evolutionary Biology, Princeton University; Princeton; NJ; 08544; USA
2. Charles Darwin Foundation; Puerto Ayora; Galapagos; Ecuador
3. Galapagos National Park; Puerto Ayora; Galapagos; Ecuador
4. State University of New York, College of Environmental Science and Forestry; Syracuse; NY; 13210; USA
5. e-obs GmbH; Gruenwald; Germany
6. Max Planck Institute for Ornithology; Radolfzell; Germany