1. Department of Bird Migration, Swiss Ornithological Institute, Sempach, Switzerland
2. Department of Zoology, Palacký University, Olomouc, Czech Republic
3. Museum of Natural History, Olomouc, Czech Republic
4. Department of Biology and Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Aveiro, Portugal
5. South Iceland Research Centre, University of Iceland, Laugarvatn, Iceland
6. Department of Animal Ecology/Ecology and Genetics, Uppsala University, Uppsala, Sweden
7. Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic