1 Migratory Waterbirds in the Wadden Sea 1987- 2008 WADDEN SEA ECOSYSTEM No. 30 - 2010 Wadden Sea Ecosystem No. 30 2010 2 Wadden Sea Ecosystem No. 30 2010 1 Migratory Waterbirds in the Wadden Sea 1987- 2008 Trend, Phenology, Distribution and Climate Aspects Wadden Sea Ecosystem No. 30 2010 2 Colophon Publishers Common Wadden Sea Secretariat (CWSS), Wilhelmshaven, Germany; Joint Monitoring Group of Migratory Birds in the Wadden Sea (JMMB). Authors Karsten Laursen, Danmarks Miljøundersøgelser / NERI, Aarhus University, Grenåvej 12, DK 8410 Rønde; Jan Blew, BioConsult SH, Brinckmannstr. 31, D25813 Husum; Kai Eskildsen, Nationalparkverwaltung SchleswigHolsteinisches Wattenmeer, Schloßgarten 1, D 25832 Tönning; Klaus Günther, Schutzstation Wattenmeer, NationalparkHaus Hafen Husum, Hafenstraße 3, D 25813 Husum; Bernd Hälterlein, Nationalparkverwaltung SchleswigHolsteinisches Wattenmeer, Schloßgarten 1, D 25832 Tönning; Romke Kleefstra, SOVON Vogelonderzoek Nederland, Toernooiveld 1, NL6503 GA Nijmegen; Gerold Lüerßen, Common Wadden Sea Secretariat, Virchowstr. 1, D 26382 Wilhelmshaven; Petra Potel, Nationalparkverwaltung Niedersächsisches Wattenmeer, Virchowstr. 1, D 26382 Wilhelmshaven; Stefan Schrader, Landesbetrieb für Küstenschutz, Nationalpark und Meeresschutz SchleswigHolstein, HerzogAdolfStr. 1, D 25813 Husum Language support Seabury Salmon Cover photo Bo Lassen Christiansen Layout and technical editing Common Wadden Sea Secretariat Graphic support Gerold Lüerßen Print LDruck GmbH, Rastede Paper Revive Pure Natural Matt 100% Recycling Paper Number of copies 1,500 Published 2010 ISSN 0946896X This publication should be cited as: Laursen, K., Blew, J., Eskildsen, K., Günther, K., Hälterlein, B., Kleefstra, R., Lüerßen, G., Potel, P., Schrader, S. 2010. Migratory Waterbirds in the Wadden Sea 1987 2008. Wadden Sea Ecosystem No.30. Common Wadden Sea Secretariat, Joint Monitoring Group of Migratory Birds in the Wadden Sea, Wilhelmshaven, Germany. Wadden Sea Ecosystem No. 30 2010 3 WADDEN SEA ECOSYSTEM No. 30 Migratory Waterbirds in the Wadden Sea 1987- 2008 Trend, Phenology, Distribution and Climate Aspects Karsten Laursen Jan Blew Kai Eskildsen Klaus Günther Bernd Hälterlein Romke Kleefstra Gerold Lüerßen Petra Potel Stefan Schrader 2010 Common Wadden Sea Secretariat Joint Monitoring Group of Migratory Birds in the Wadden Sea In cooperation with Aarhus University, National Environmental Research Institute, Dept. of Wildlife Ecology and Biodiversity. Naturstyrelsen Ribe, Danish Ministry of the Environment and Bio Consult SH. Wadden Sea Ecosystem No. 30 2010 4 Wadden Sea Ecosystem No. 30 2010 5 Contents 1. Introduction 7 2. Summaries 9 2.1 Summary 9 2.2 Sammenfatning 11 2.3 Zusammenfassung 13 2.4 Sammenvatting 16 3. Data and Methods 19 3.1 Implementation of the JMMB Program 19 3.2 Site selection and site aggregations 19 3.3 Species selection 20 3.4 Fieldwork 20 3.5 Classification of winters 24 3.6 Data processing 25 3.6.1 Trends 25 3.6.2 Distributions and maps 26 3.6.3 Phenologies and figures 26 3.6.4 Maximum estimates 26 3.7 Presentation of data 28 4. Quality of Data 31 4.1. Coverage of mainstaging areas through site selection 31 4.2. Reliability of counted and estimated totals 31 5. Species Accounts 32 5.1 Great Cormorant 33 5.2 Eurasian Spoonbill 36 5.3 Barnacle Goose 39 5.4 Dark-bellied Brent Goose 42 5.5 Common Shelduck 45 5.6 Eurasian Wigeon 48 5.7 Common Teal 51 5.8 Mallard 54 5.9 Northern Pintail 57 5.10 Northern Shoveler 60 5.11 Common Eider 63 5.12 Eurasian Oystercatcher 66 5.13 Pied Avocet 69 5.14 Great Ringed Plover 72 5.15 Kentish Plover 75 5.16 Eurasian Golden Plover 78 5.17 Grey Plover 81 5.18 Northern Lapwing 84 5.19 Red Knot 87 5.20 Sanderling 90 5.21 Curlew Sandpiper 93 5.22 Dunlin 96 5.23 Ruff 99 Wadden Sea Ecosystem No. 30 2010 6 5.24 Bar-tailed Godwit 102 5.25 Whimbrel 105 5.26 Eurasian Curlew 108 5.27 Spotted Redshank 111 5.28 Common Redshank 114 5.29 Common Greenshank 117 5.30 Ruddy Turnstone 120 5.31 Common Black-headed Gull 123 5.32 Common Gull 126 5.33 Herring Gull 129 5.34 Great Black-backed Gull 132 6. Overviews on Trends and Changes in Distribution or Phenology 135 6.1 Trends over 21 year 135 6.2 Change in geographical distribution 136 6.3 Change in phenology 137 6.4 Numbers in relation to flyway numbers 138 7. Discussion 139 7.1 Trends 139 7.2. Numbers and direct and indirect effects of climate changes 143 7.3 The Wadden Sea inperspective 145 8. References 149 Appendix 1 155 Acknowledgements 161 Wadden Sea Ecosystem No. 30 2010 7 1. Introduction The Wadden Sea is among the largest coastal The report is produced by the National Co wetlands in the world. It is a key area and the ordinating Group on the Joint Monitoring of most important staging site along the East At Migratory Birds (JMMB) under the Trilateral lantic Flyway for birds moving between breeding Monitoring and Assessment Program. During the areas in the Arctic from Canada/Greenland in the preparatory work of the report Bettina Reineking west to Siberia in the east to wintering areas in from the Wadden Sea Secretariat and Mark van West Europe, the Mediterranean and Africa. The Roomen from SOVON, The Netherlands, was part Wadden Sea’s shallow, tidal influenced waters, of the JMMBgroup and they both gave valuable its extensive tidal flats and adjacent saltmarshes support and suggestions for the work. We all of provide food for about 12 million waterbirds fer our sincere thanks for the time they spent in which stop to build up their fat reserves for their the group and their work on migratory birds. further migration, moulting during autumn or Since the last migratory bird report (Blew et staging during winter. At least 52 populations of al., 2007), the Dutch and German parts of the 41 migratory waterbirds use the Wadden Sea an Wadden Sea Conservation Area were designat nually. Of these, the numbers of 44 populations ed as a World Heritage Site by UNESCO in June of 34 species are large enough for the Wadden 2009 (Common Wadden Sea Secretariat, 2008). Sea to be considered as their most important This was a great step in formally recognizing the stopover site during migration (Meltofte et al., global importance of the Wadden Sea. Since this 1994, Blew et al., 2005a). report covers the period up to the designation The purpose of this report is twofold, 1) to year, the result of these analyses can be consid update the knowledge and numbers of the mi ered as a baseline for future comparison of de gratory birds for the QSR 2009 report. In that re velopments in the Wadden Sea. port, the species numbers are assessed in relation to targets in the Wadden Sea plan (Laursen et al., 2009, Wadden Sea Plan, 1997); and 2) to provide the most recent information and data of the mi gratory birds in the Wadden Sea, including the species phenology, geographical distribution and numbers. In the present report these aspects are also analysed in relation to climate and regional aspects. Since the report published by Meltofte et al. (1994) species distribution has not been estimated; while in the interim period focus has been on population numbers and trends (Rösner et al., 1994, Poot et al., 1996) and new statis tical methods have been introduced and results have been provided (Blew et al., 2005a, Blew et al., 2007). The data presented in this report is a part of the Trilateral Monitoring and Assessment Pro gram for the Wadden Sea gathered by the Joint Monitoring of Migratory Birds program. It con sists of (a) at least 23 synchronous, complete, counts each year, and (b) bimonthly counts dur ing spring tide at 60 counting sites and (c) ad ditional three counts for geese and aerial counts for Shelduck and Eider. The trilateral counts were initiated in 1980 and from 1987/1988 a solid counting scheme was established, which makes it possible to produce trends calculated not only from winter or autumn, but on yearround data. To do this, missing data are substituted by cal culated numbers to fill in gaps in the counts. This paper presents results from 1987/1988 2007/2008, thus covering a period of 21 years. Wadden Sea Ecosystem No. 30 2010 8 Photo: Gundolf Reichert Wadden Sea Ecosystem No. 30 2010 9 2. Summaries 2.1 Summary during the annual cycle. In addition, seven spe cies are present with more than 50 % of their The Wadden Sea along the west coast of Den flyway population and a further 13 species with mark, Germany and The Netherlands holds the more than 10 %. In addition the coastal zone largest coherent tidal flat in the world. The size of the offshore area is used by high numbers of including the offshore area (to 15 m depth) is moulting Shelduck Tadorna tadorna and moult 2 roughly 14.700 km , of which the intertidal flats ing and wintering Common Eider Somateria mol- make up a third of the area and the saltmarsh lissima. es about 3 %. Due to nutrition inflow from the During the last decade, the JMMBgroup had North Sea and the rivers, the Wadden Sea habi focused on estimating trends for the migratory tats provide a rich food source for birds all year birds in the Wadden Sea (Blew et al. 2005), re around. vealing serious declines in some species numbers The Wadden Sea is the single most important (Blew et al. 2007). In this report, beside the trend staging, moulting and wintering area for water estimates, the JMMBgroup focuses on geo birds on the East Atlantic flyway. According to graphical distribution and phenology of the mi the 1% criterion of the Ramsar Convention, the gratory species in relation to the environmental Wadden Sea is of outstanding international im and climatic dynamics in the Wadden Sea.