1. Wildfowl & Wetlands Trust, Slimbridge, Gloucestershire, GL2 7BT, UK
2. Langahlíð 9a, 603 Akureyri, Iceland
3. BirdLife Iceland, PO Box 5069, IS-125, Reykjavík, Iceland
4. Latvian National Museum of Natural History, Kr. Barona iela 4, Rīga, LV-1050, Latvia
5. Laboratory of Ornithology, Institute of Biology, University of Latvia, O. Vācieša iela 4, Rīga, LV-1004, Latvia
6. Brautarland 2, 108 Reykjavík, Iceland
7. Icelandic Institute of Nature History, 6–8, 210, Urriðaholtsstræti, Garðabær, Iceland
8. Irish Whooper Swan Study Group, 100 Strangford Road, Downpatrick, Co Down, BT30 7JD, UK
9. Elsa-Brandström-Str. 4, D-49076 Osnabrück, Germany
10. Aavænget 12, Voersaa, 9300 Sæby, Denmark
11. Ved Stranden 8, 3630 Jægerspris, Denmark
12. Østfold University College, Halden, Norway and BirdLife Norway, Sandgata 30 B, 7012 Trondheim
13. Royal Belgian Institute of Natural Sciences, Museum of Natural Sciences, Vautier Street 29, 1000 Brussels, Belgium
14. Veldstukken 15, 9761 JX Eelde, Netherlands
15. Ornithological Station, Institute and Museum of Zoology, Polish Academy of Science, Nadwiślańska 108, 80-680 Gdańsk, Poland
16. Estonian University of Life Sciences, Institute of Agriculture and Environmental Sciences, Kreutzwaldi 5, 51006, Tartu, Estonia
17. Marine Research Institute, Klaipėda University, Universiteto ave. 17, LT-92294 Klaipėda, Lithuania
18. 166700, Russia Nenets AO, Iskateley, Pomorskaya St. 16-23, Russia
19. National Academy of Sciences of Belarus, 27 Akademicheskaya Street, Minsk, BY-220072, Belarus
20. Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK