1. Department of Zoology and Laboratory of Ornithology Faculty of Science Palacky University Olomouc Czech Republic
2. Department of Animal Behaviour Bielefeld University Bielefeld Germany
3. Institute of Vertebrate Biology Czech Academy of Sciences Brno Czech Republic
4. Department of Zoology Faculty of Science Charles University in Prague Prague Czech Republic
5. Evolutionary Biology Bielefeld University Bielefeld Germany
6. Museum of Natural History Olomouc Czech Republic