1. 1 University of Eastern Finland , Koskikatu 9B31, 80100 Joensuu , Finland
2. 2 Länsirannantie 297 , Mäyry , Finland .
3. 3 Institute of Agricultural and Environmental Sciences , Estonian University of Life Sciences , Tartu , Estonia .
4. 4 Institute of Biology , University of Latvia , Riga , Latvia .
5. 5 Ventės Ragas Ornithological Station , Ventė, Kintai , Lithuania .
6. 6 Department of Ecology and Anthropology, Institute of Biology , University of Szczecin , Wąska 13, 71-412 Szczecin , Poland / Department of Avian Biology and Ecology, Faculty of Biology , Adam Mickiewicz University , Poznań , Uniwersytetu Poznańskiego 6, 61-614 Poznań , Poland .
7. 7 Laboratory of Molecular Zoology , National Academy of Sciences of Belarus , Minsk , Belarus .
8. 8 Rostocker Str. 108, DE-26121 Oldenburg , Germany .
9. 9 National Museum of the Czech Republic , Praha , Czech Republic .
10. 10 State Nature Conservancy of Slovakia , Bratislava , Slovakia .
11. 11 Schmalhausen Institute of Zoology, NAS of Ukraine , Kyiv , Ukraine .
12. 12 Swiss Ornithological Institute , Sempach , Switzerland .