1. Department of Ecology Faculty of Science Charles University Viničná 7 Prague 2 CZ‐12844 Czech Republic
2. Department of Invasion Ecology Institute of Botany The Czech Academy of Sciences Zámek 1 Průhonice CZ‐252 43 Czech Republic
3. Czech Society for Ornithology Na Bělidle 34 Prague 5 CZ‐15000 Czech Republic
4. Institute of Vertebrate Biology The Czech Academy of Sciences Květná 8 Brno CZ‐60365 Czech Republic