1. Conservation Biology & Ecology Program; Department of Ecology; Montana State University; Bozeman; Montana; 59717; USA
2. Department of Zoology; Michigan State University; East Lansing; Michigan; 48824; USA
3. Abteilung Verhaltensneurobiologie; Max-Planck-Institut für Ornithologie; Eberhard-Gwinner-Straße; Haus 6a; D-82319; Seewiesen; Germany
4. Department of Ecology, Evolution and Environmental Biology; Columbia University; 10th Floor Schermerhorn Extension; MC 5557; 1200 Amsterdam Avenue; New York; New York; 10027; USA