1. Department of Population Ecology, Institute of Ecology and Evolution, Friedrich-Schiller-University Jena , Jena , Germany
2. Natural History Museum Bern , Bern , Switzerland
3. Institute of Ecology and Evolution, University of Bern , Bern , Switzerland
4. Swiss Ornithological Institute , Sempach , Switzerland
5. Museum of Vertebrate Zoology, University of California , Berkeley, CA , USA
6. Department of Integrative Biology, University of California , Berkeley, CA , USA
7. School of Biological Sciences, University of East Anglia , Norwich , United Kingdom
8. Department of Organismal Biology – Systematic Biology (EBC), Science for Life Laboratory, Evolutionary Biology Centre, Uppsala University , Uppsala , Sweden
9. German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig , Leipzig , Germany