[1
]GRID grid.8273.e, ISNI 0000 0001 1092 7967, School of Biological Sciences, , University of East Anglia, ; Norwich, UK
[2
]GRID grid.9845.0, ISNI 0000 0001 0775 3222, Faculty of Biology, , University of Latvia, ; Jelgavas iela 1, Riga, LV-1004 Latvia
[3
]Latvian Ornithological Society, Skolas iela 3, Riga, LV-1010 Latvia
[4
]GRID grid.511845.c, Romanian Ornithological Society/BirdLife Romania, ; Cluj-Napoca, Romania
[5
]GRID grid.7399.4, ISNI 0000 0004 1937 1397, Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, , Babeș-Bolyai University, ; Cluj-Napoca, Romania
[6
]InForest JRU (CTFC-CREAF), Solsona, 25280 Spain
[7
]GRID grid.452388.0, ISNI 0000 0001 0722 403X, CREAF, Cerdanyola del Vallès, ; 08193 Barcelona, Spain
[8
]GRID grid.4711.3, ISNI 0000 0001 2183 4846, CSIC, Cerdanyola del Vallès, ; 08193 Barcelona, Spain
[9
]GRID grid.413454.3, ISNI 0000 0001 1958 0162, Museum and Institute of Zoology, , Polish Academy of Sciences, ; Wilcza 64, 00-679 Warszawa, Poland
[10
]Polish Society for the Protection of Birds (OTOP), ul. Odrowaza 24, 05-270 Marki,
Poland
[11
]Sociedad Española de Ornitología (SEO/BirdLife), Madrid, Spain
[12
]Dansk Ornitologisk Forening, BirdLife Denmark, Vesterbrogade 138-140, DK-1620 København
V, Denmark
[13
]GRID grid.475834.9, European Bird Census Council-Czech Society for Ornithology, ; Na Bělidle 34, 15000 Prague 5, Czechia
[14
]GRID grid.511627.6, European Bird Census Council–Catalan Ornithological Institute, , Natural History Museum of Barcelona, ; Plaça Leonardo da Vinci 4-5, 08019 Barcelona, Catalonia Spain
[15
]GRID grid.463835.f, ISNI 0000 0004 0445 9628, Centre d’Ecologie et des Sciences de la Conservation, UMR7204 MNHN-CNRS-SU, ; Paris, France
[16
]GRID grid.420127.2, ISNI 0000 0001 2107 519X, Norwegian Institute for Nature Research, ; P.O. Box 5685, Torgarden, NO-7485 Trondheim, Norway
[17
]GRID grid.7450.6, ISNI 0000 0001 2364 4210, University of Göttingen, Department of Conservation Science, ; Bürgerstr. 50, 37073 Göttingen, Germany
[18
]Dachverband Deutscher Avifaunisten (DDA), An den Speichern 2, 48157 Münster, Germany
[19
]DOPPS - BirdLife Slovenia, Tržaška cesta 2, SI-1000 Ljubljana, Slovenia
[20
]GRID grid.507626.0, ISNI 0000 0001 0684 4026, Finnish Museum of Natural History, FI-00014 University of Helsinki, ; P.O. Box 17, Helsinki, Finland
[21
]GRID grid.4514.4, ISNI 0000 0001 0930 2361, Biodiversity Unit, Department of Biology, , Lund University, ; Ecology Building, S-223 62 Lund, Sweden
[22
]GRID grid.423196.b, ISNI 0000 0001 2171 8108, British Trust for Ornithology, , The Nunnery, ; Thetford, Norfolk, IP24 2PU UK
[23
]NOF-BirdLife Norway, Sandgata 30 B, NO-7012 Trondheim, Norway
[24
]Natagora, Département Études, Traverse des Muses 1, B-5000 Namur, Belgium
[25
]GRID grid.4491.8, ISNI 0000 0004 1937 116X, Institute for Environmental Studies, , Faculty of Science, Charles University in Prague, ; Prague, Czechia
[26
]GRID grid.10979.36, ISNI 0000 0001 1245 3953, Department of Zoology and Laboratory of Ornithology, Faculty of Science, , Palacký University Olomouc, ; 17 Listopadu 50, 771 43 Olomouc, Czechia
[27
]GRID grid.419767.a, ISNI 0000 0001 1512 3677, Swiss Ornithological Institute, ; Seerose 1, 6204 Sempach, Switzerland
[28
]BirdLife Österreich, Museumsplatz 1/10/8, A-1070 Wien, Austria
[29
]GRID grid.452751.0, ISNI 0000 0004 0465 6808, Sovon Dutch Centre for Field Ornithology, ; P.O. Box 6521, 6503 GA Nijmegen, Netherlands
[30
]GRID grid.5590.9, ISNI 0000000122931605, Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research,
, Radboud University, ; P.O. Box 9010, 6500 GL Nijmegen, Netherlands
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