[1] Czech Soc Ornithol, Prague 15000, Czech Republic
[2] InForest Jru, CEMFOR CTFC, Solsona 25280, Spain
[3] Nat Hist Museum Barcelona, Catalan Ornithol Inst, Barcelona 08019, Spain
[4] Ctr Recerca Ecol & Aplicac Forestals, Bellaterra 08193, Spain
[5] CSIC, Cerdanyola Del Valles 08193, Spain
[6] European Bird Census Council, Nijmegen, Netherlands
[7] BirdLife Europe, B-1060 Brussels, Belgium
[8] Sovon Dutch Ctr Field Ornithol, NL-6503 Nijmegen, Netherlands
[9] Radboud Univ Nijmegen, Inst Water & Wetland Res, Dept Anim Ecol & Ecophysiol, NL-6500 Nijmegen, Netherlands
[10] LIPU BirdLife Italy, Coordinamento Nazl MITO2000, I-43122 Parma, Italy
[11] RSPB Ctr Conservat Sci, Sandy SG19 2DL, Beds, England
[12] Charles Univ Prague, Dept Ecol, CR-12844 Prague, Czech Republic
[13] UPMC, Sorbonne Univ, CNRS, UMR7204,CESCO,MNHN, F-75005 Paris, France
[14] DOPPS BirdLife Slovenia, Ljubljana 1001, Slovenia
[15] Univ Helsinki, Finnish Museum Nat Hist, Helsinki Lab Ornithol, FIN-00014 Helsinki, Finland
[16] Lund Univ, Dept Biol, Biodivers Unit, S-22362 Lund, Sweden
[17] Natagora, Dept Etud, B-5000 Namur, Belgium
[18] Charles Univ Prague, Fac Sci, Inst Environm Studies, Prague 12801, Czech Republic
[19] Palacky Univ, Fac Sci, Dept Zool, Olomouc 77146, Czech Republic
[20] Palacky Univ, Fac Sci, Ornithol Lab, Olomouc 77146, Czech Republic
[21] Stat Netherlands, NL-2492 The Hague, Netherlands
[22] Univ Nyiregyhaza, H-4400 Nyiregyhaza, Hungary
[23] Acad Sci Czech Republ, Inst Vertebrate Biol, CS-60365 Brno, Czech Republic
[24] BirdLife Osterreich, A-1070 Vienna, Austria
[25] Dachverband Deutsch Avifaunisten, D-48157 Munster, Germany
[26] BirdLife Denmark DOF, DK-1620 Copenhagen, Denmark