Wasservögel im internationalen Rheintal: Zahlen, Verbreitung und Trends (EN) Bericht Nr. 277 Impressum Herausgeberin: Internationale Kommission zum Schutz des Rheins (IKSR) Kaiserin-Augusta-Anlagen 15, D 56068 Koblenz Postfach 20 02 53, D 56002 Koblenz Telefon +49-(0)261-94252-0, Fax +49-(0)261-94252-52 E-mail: [email protected] www.iksr.org © IKSR-CIPR-ICBR 2020 IKSR CIPR ICBR Authors: Marc van Roomen1, Fred Hustings1, Erik van Winden1, Christian Dronneau2, Christian Frauli2, Nicolas Strebel3, Johannes Wahl4, Kees Koffijberg1 & Chris van Turnhout1 With contributions from: Rüdiger Burkhardt5, Bernhard Disch6, Thomas Dolich7, Albrecht Frenzel8, Menno Hornman1, Veronika Huisman-Fiegen9, Harald Jacoby10, André van Kleunen1, Mona Kuhnigk9, Tom Langendoen11, Jochen Lehmann8, Nikolas Prior4, Jan Schoppers1 & Stefan R. Sudmann9 1 Sovon Vogelonderzoek Nederland 2 Ligue pour la Protection des Oiseaux d’Alsace, France 3 Schweizerische Vogelwarte Sempach 4 Dachverband Deutscher Avifaunisten 5 Hessische Gesellschaft für Ornithologie und Naturschutz 6 Fachschaft für Ornithologie Südlicher Oberrhein 7 Gesellschaft für Naturschutz und Ornithologie Rheinland-Pfalz 8 Ornithologische Arbeitsgemeinschaft Karlsruhe 9 Nordrhein-Westfälische Ornithologengesellschaft 10 Ornithologische Arbeitsgemeinschaft Bodensee 11 Wetlands International Commissioned by: Rijkswaterstaat, Ministerie van Verkeer en Waterstaat, The Netherlands A co-production of: Sovon Vogelonderzoek Nederland, Schweizerische Vogelwarte Sempach, Ligue pour la Protection des Oiseaux d’Alsace and Dachverband Deutscher Avifaunisten Photos: Harvey van Diek, Cor Fikkert, Hans Gebuis, Rein Hofman, Marcel van Kammen, Ralph Martin (Agami), Theo Verstrael, Gejo Wassink Lay-out & Production: Nikola Schulte-Kellinghaus International Commission for the Protection of the Rhine (ICPR) Recommended citation: van Roomen, M., Hustings, F., van Winden, E., Dronneau, C., Frauli, C., Strebel, N.,Wahl, J., Koffijberg, K. & van Turnhout, C. 2020. Waterbirds in the international Rhine Valley: numbers, distribution and trends. ICPR rap nr. 277, Sovon rap nr. 2020/99. International Commission for the Protection of the Rhine, Koblenz. 277en 2 IKSR CIPR ICBR Contents Acknowledgements ............................................................................................ 5 Summary ............................................................................................................ 6 Zusammenfassung.............................................................................................. 8 Résumé .............................................................................................................10 Samenvatting ....................................................................................................13 1. Introduction ..................................................................................................16 2. Study area .....................................................................................................18 3. Methods .........................................................................................................21 3.1. Organisation ...............................................................................................21 3.2. Census areas ..............................................................................................22 3.3. Fieldwork ...................................................................................................23 3.4. Data analysis ..............................................................................................24 3.4.1. General aspects .....................................................................................24 3.4.2. Distribution ...........................................................................................24 3.4.3. Seasonal pattern ...................................................................................25 3.4.4. Trends January 1981-2018 .....................................................................25 4. Results ..........................................................................................................26 4.1. General results ...........................................................................................26 4.1.1. Status in 2015/16 – 2017/18 ..................................................................26 4.1.2. Trends January 1981-2018 .....................................................................31 4.2. Species accounts .........................................................................................38 4.2.1 Little Grebe Tachybaptus ruficollis .............................................................39 4.2.2 Great Crested Grebe Podiceps cristatus .....................................................41 4.2.3 Black-necked Grebe Podiceps nigricollis .....................................................43 4.2.4 Great Cormorant Phalacrocorax carbo sinensis ...........................................45 4.2.5 Grey Heron Ardea cinerea ........................................................................48 4.2.7 Whooper Swan Cygnus cygnus .................................................................52 4.2.8 Tundra Bean Goose Anser serrirostris ........................................................54 4.2.9 Greylag Goose Anser anser ......................................................................56 4.2.10 Greater White-fronted Goose Anser albifrons ............................................59 4.2.11 Greater Canada Goose Branta canadensis canadensis ................................61 4.2.12 Egyptian Goose Alopochen aegyptiacus....................................................63 4.2.13 Ruddy Shelduck Tadorna ferruginea ........................................................65 4.2.14 Eurasian Wigeon Mareca penelope ..........................................................67 4.2.15 Gadwall Anas strepera ...........................................................................69 4.2.16 Eurasian Teal Anas crecca ......................................................................71 4.2.17 Mallard Anas platyrhynchos ....................................................................73 4.2.18 Northern Pintail Anas acuta ....................................................................75 4.2.19 Northern Shoveler Anas clypeata ............................................................77 277en 3 IKSR CIPR ICBR 4.2.20 Red-crested Pochard Netta rufina ............................................................79 4.2.21 Common Pochard Aythya ferina ..............................................................81 4.2.23 Common Goldeneye Bucephala clangula ..................................................86 4.2.24 Smew Mergellus albellus ........................................................................88 4.2.25 Common Merganser Mergus merganser ...................................................90 4.2.27 Black-headed Gull Chroicocephalus ridibundus ..........................................94 4.2.28 Mew Gull Larus canus ............................................................................96 5. Discussion and conclusions ......................................................................... 100 5.1. Advances in data collection and analyses ..................................................... 100 5.2. Waterbird numbers and responses to ecological change ................................. 100 5.3. Conservation status of waterbirds in the Rhine Valley .................................... 101 5.4. Main conclusions ....................................................................................... 103 5.5. Recommendations for monitoring ................................................................ 104 6. References ................................................................................................... 106 Annex 1. Observers in the Rhine valley from winter 2015/16 onwards ........... 115 Annex 2. Species names .................................................................................. 118 Annex 3. Amount imputing per species and area ............................................. 120 Annex 4. Species attributes ............................................................................. 122 277en 4 IKSR CIPR ICBR Acknowledgements This study was made possible through financial support from Rijkswaterstaat, The Netherlands. Gerrit Vossebelt and Allard Hiddink are thanked for arranging this. From Rijkswaterstaat valuable guidance and comments on a first draft were received from Gerrit Vossebelt and Mervyn Roos. This report is based on census data covering a timespan of mearly 40 years! In recent years alone, about 700 dedicated birdwatchers have contributed (see annex 1). They are largely skilled volunteers, carrying out the field work in their spare time, supplemented with professionals from research institutes and nature management organizations. Coordination at the regional, national and international level is essential to run such a large-scale network for bird monitoring successfully. The waterbird census in Switzerland is coordinated by Vogelwarte Sempach by Nicolas Strebel and supported by the Federal Office of the Environment (Bundesamt für Umwelt BAFU, Switzerland). The regional coordination for the Bodensee is done by Harald Jacoby, Ornithologische Arbeitsgemeinschaft Bodensee. The waterbird census in France is coordinated by Ligue pour la Protection des Oiseaux (LPO), Regional coordination at the French side of the “Oberrhein” (called