1. Department of Behavioural Ecology & Evolutionary Genetics; Max Planck Institute for Ornithology; Seewiesen Germany
2. Department of Migration and Immuno-Ecology; Max Planck Institute for Ornithology; Radolfzell Germany
3. University of Konstanz; Konstanz Germany
4. Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
5. Environment and Sustainability; Institute, University of Exeter; Penryn Cornwall UK