1. Max Planck Institute of Animal Behavior Radolfzell Germany
2. Department of Biology University of Konstanz Konstanz Germany
3. Department of Zoology Faculty of Science Charles University Prague 2 Czech Republic
4. Department of Behavioural Neurobiology Max Planck Institute for Ornithology Seewiesen Germany
5. Faculty of Biology University of Białystok Białystok Poland
6. Mammal Research Institute Polish Academy of Sciences Białowieża Poland