WADDEN SEA ECOSYSTEM No. 39 - 2019

Trends of Migratory and Wintering Waterbirds

in the Wadden Sea 1987/1988-2016/2017

Migratory birdProgress trends until 2016/2017 Report

Publishers Common Wadden Sea Secretariat (CWSS), Wilhelmshaven, Germany; Joint Monitoring Group of Migratory Birds in the Wadden Sea (JMMB).

Authors Romke Kleefstra, SOVON Vogelonderzoek Nederland, p/a Natuurmuseum Fyslân, Schoenmakersperk 2, NL - 8911 EM Leeuwarden; Menno Hornman, SOVON Vogelonderzoek Nederland, Natuurplaza, Toernooiveld 1 NL - 6525 ED Nijmegen;

Thomas Bregnballe, Aarhus University, Department of Bioscience - Wildlife Ecology, Grenåvej 14 DK- 8410 Rønde, John Frikke, Nationalpark Vadehavet, Havnebyvej 30 DK - 6792 Rømø Klaus Günther, Schutzstation Wattenmeer, NationalparkHaus Hafen Husum, Hafenstraße 3, D - 25813 Husum;

Bernd Hälterlein, Nationalparkverwaltung Schleswig-Holsteinisches Wattenmeer, Schloßgarten 1, D-25832 Tönning; Peter Körber, Behörde für Stadtentwicklung und Umwelt (BSU), Neuenfelder Straße 19 D - 21109 Hamburg; Jürgen Ludwig, State Agency for Bird Conservation in the Lower Saxony Water Management, Coastal Defence and Nature Conservation Agency (NLWKN), Göttinger Chaussee 76 A, D - 30453 Hannover; Gregor Scheiffarth, Nationalparkverwaltung Niedersächsisches Wattenmeer, Virchowstr. 1, D - 26382 Wilhelmshaven Trend calculations Erik van Winden (SOVON, The Netherlands) performed the UINDEX and TrendSpotter operations to cal- culate trends and to provide the imputed numbers for the calculation of maximum estimates and dis- tributions.

Title photo Klaus Günther Drawings Niels Knudsen Coordination and layout Gerold Lüerßen

The publication should be cited as: Kleefstra R., Hormann M., Bregnballe T., Frikke J., Günther K., Hälterlein B., Körber P., Scheiffarth G., 2019. Trends of Migratory and Wintering Waterbirds in the Wadden Sea 1987/1988 - 2016/2017. Wadden Sea Ecosystem No. 39. Common Wadden Sea Secretariat, Joint Monitoring Group of Migratory Birds in the Wadden Sea, Wilhelmshaven, Germany.

Migratory bird trends until 2016/2017

Progress Report

Trends of Migratory and Wintering

Waterbirds in the Wadden Sea

1987/1988 - 2016/2017

Romke Kleefstra Menno Hornman

Thomas Bregnballe John Frikke Klaus Günther Bernd Hälterlein

Peter Körber

Jürgen Ludwig Gregor Scheiffarth

2019 Common Wadden Sea Secretariat Joint Monitoring Group of Migratory Birds in the Wadden Sea

Migratory bird trends until 2016/2017

Content

1 Introduction 5

2 Data and methods 6

3 Overview trends 8 4 Species accounts 13 4.1 Great Cormorant 15 4.2 Eurasian Spoonbill 16 4.3 Barnacle Goose 17 4.4 Dark-bellied Brent Goose 18 4.5 Common Shelduck 19 4.6 Eurasian Wigeon 20 4.7 Common Teal 21 4.8 Mallard 22 4.9 Northern Pintail 23 4.10 Northern Shoveler 24 4.11 Common Eider 25 4.12 Eurasian Oystercatcher 26 4.13 Pied Avocet 27 4.14 Great Ringed Plover 28 4.15 Kentish Plover 29 4.16 European Golden Plover 30 4.17 Grey Plover 31 4.18 Northern Lapwing 32 4.19 Red Knot 33 4.20 Sanderling 34 4.21 Curlew Sandpiper 35 4.22 Dunlin 36 4.23 Ruff 37 4.24 Bar-tailed Godwit 38 4.25 Whimbrel 39 4.26 Eurasian Curlew 40 4.27 Spotted Redshank 41 4.28 Common Redshank 42 4.29 Common Greenshank 43 4.30 Ruddy Turnstone 44 4.31 Common Black-headed Gull 45 4.32 Common Gull 46 4.33 Herring Gull 47 4.34 Great Black-backed Gull 48 5 Subspecies accounts 49 5.1 Great Ringed Plover (hiaticula) 50 5.2 Great Ringed Plover (psammodroma/tundrae) 51 5.3 Red Knot (canutus) 52 5.4 Red Knot (islandica) 53 5.5 Bar-tailed Godwit (taymyrensis) 54 5.6 Bar-tailed Godwit (lapponica) 55 5.7 Common Redshank (totanus) 56 5.8 Common Redshank (robusta) 57 5.9 Ruddy Turnstone (Greenland & NE Canada) 58 5.10 Ruddy Turnstone (Scandinavia-Western Russia) 59 6 References 60 Annex 1 Assignment of species according to living conditions 62 Annex 2 Counting units in the Wadden Sea 64

Annex 3 Species list 66

Migratory bird trends until 2016/2017

1 Introduction

Monitoring migratory and wintering The Netherlands, the Federal States of Germany, birds, the JMMB program Niedersachsen and Schleswig-Holstein, and Den- mark will be presented. The Wadden Sea constitutes one of the world’s Details of the “Joint Monitoring program of most important wetlands for migratory water- Migratory Birds in the Wadden Sea” are given in birds. It is the single most important staging and Rösner et al., (1993) and updated in Laursen et moulting area and an important wintering area al. (2010). This program, consisting of interna- for waterbirds on the East Atlantic Flyway from tional synchronous counts, spring-tide counts the Arctic to South Africa. The Joint Monitoring and aerial counts (only Common Eider), has been of Migratory Birds (JMMB) program is carried out carried out by all Wadden Sea countries since in the framework of the Trilateral Monitoring and 1992. Some differences between the countries’ Assessment Program (TMAP), and constitutes an programs exist, due to different national ap- internationally coordinated long-term monitor- proaches and older already existing counting ing program. It covers a large connected eco- programs, but these do not hamper the overall region stretching from Den Helder in The Neth- goal for calculating trends. Because many usable erlands to Esbjerg in Denmark; regular ground counting data before 1992 exist as well, it has counts for most species and areas plus aerial been decided to include counts back to the sea- counts for sea ducks involves hundreds of ob- son 1987/1988. servers and several institutes and agencies. The area considered is the Wadden Sea Coop- After the publication of trends, comprehen- eration Area. This is, in general terms, the area sive species accounts and assessments in the seaward of the main dike (or, where the main most recent reports (Blew et al. 2015 and Blew dike is absent, the spring-high-tide-water line, et al. 2016), the JMMB group agreed, that from and in the rivers, the brackish-water limit) up to now on every two years an update of these trend 3 nautical miles from the baseline or the offshore calculation shall be published on this website. boundaries of the Conservation Area (Essink et Here, trends of 34 waterbird species for the in- al., 2005). The total area covers 14,700 km², with ternational Wadden Sea and the four regions - 4,534 km² of tidal flats.

Drawing: Niels Knudsen

Migratory bird trends until 2016/2017 6 Introduction

2 Data and methods

Data used in the analyses are a mixture of total late trends (Visser, 2004, Soldaat et al 2007). The counts (two internationally, up to five nation- program UINDEX is estimating bird numbers for ally) and counts of a selection of sites which are missing counts (imputing) taking into account counted more frequently (12-25 times a season). site-, year- and month-factors (Underhill & Prys- At present a total of 594 counting units are de- Jones 1994). Sites are grouped in four regional fined in the Wadden Sea, which are included in strata representing the four different Wadden the analyses. For this report, the original count- Sea “countries”. The counted and imputed values ing data, available at the smallest level have for each month are added to yearly averages for been used. the respective “bird-years”, covering the period Trends are calculated and presented for 34 from July to June of the following year (Fig. 2.1). waterbird species. These are species which use After that with the program TrendSpotter so- the Wadden Sea during stop-over on migration called “flexible trends” are calculated. These are or as a wintering area with large parts of their particularly suitable for time series data with dif- flyway population. For 10 different subspecies of ferent periods of decreasing, stable or increasing 5 of these 34 species trends are calculated also, trends (Visser 2004, Soldaat et al., 2007). A trend since the subspecies can be separated by differ- line calculated by TrendSpotter hardly deviates ent periods of their presence in the Wadden Sea from a moving average or a smoothed trend line area during the year. Trends for subspecies are as calculated by a Generalized Additive Model calculated for Common Ringed-Plover, Red Knot, (GAM) (e.g. Atkinson et al., 2006). TrendSpotter Bar-tailed Godwit, Redshank and Turnstone. calculates also confidence intervals and differ- Species which only occur in low numbers or spe- ences between the trend level of the last year cies which cannot be counted with sufficient and each of the preceding years can be assessed representativeness have been excluded from the (Soldaat et al. 2007). This way trend estimates analyses (for a more detailed explanation see can be given for any period, as for example the Rösner et al., 1994). last 10 years and the whole time period, as in the Despite a large dataset with lots of real count current analyses. data available also missing counts are present. A Trend estimates given within the text are used complete dataset involves counts for all count- as categories (Fig. 2.2). ing units in all months of the year. To analyse the This progress report presents data of the pe- waterbird count data, UINDEX (Bell, 1995) was riod 1987/1988 - 2016/2017. used to account for missing counts in the dataset, and then TrendSpotter is applied to calcu- Figure 2.1 counted and imputed season 2007/2008 trend on average number Example of the treat- 140,000 80,000 ment of data for the trend 120,000 70,000 analyses. First the seasonal pattern is reconstructed by 100,000 60,000 50,000 using counted numbers and 80,000 imputed numbers for each 40,000 month for a certain species Number 60,000 Number average number 30,000 (left graph of the figure, dark 40,000 blue is counted, light blue is 20,000 imputed). Than the average 20,000 10,000 over all months is taken and 0 0 this is the ‘yearly estimate’ jul aug sep oct nov dec jan feb mar apr may jun 1985 1990 1995 2000 2005 2010 to be used in the trend analyses (right graph). The averaged yearly annual change trend line and confidence limits are calculated over all 0.95 1.00 1.05 trend categories year estimates. strong de- or increase

moderate de- or increase

Figure 2.2 moderate de- or increase Trend classification used to express annual changes in stable waterbird numbers. Dots represent trend values, uncertain / uctuating horizontal lines their 95% uncertain / uctuating confidence limits.

Migratory bird trends until 2016/2017

2 Data and methods 7

Acknowledgements Schleswig-Holstein Wadden Sea. In Hamburg counts were organized by the In Denmark the counts were carried out by Hamburg Wadden Sea National Park. DCE - Danish Centre for Environment and Ener- In Niedersachsen the counts were organized gy, Aarhus University. Aerial counts were carried by the State Agency for Bird Conservation in out by Aarhus University and BIOVEST; in earlier the Lower Saxony Water Management, Coast- years by the former Danish National Environ- al Defence and Nature Conservation Agency mental Research Institute NERI in collaboration (NLWKN). The aerial surveys of Common Eider with local departments of the Ministry of the were financed by the Lower Saxony Wadden Sea Environment. National Park Authority. In Schleswig-Holstein the monitoring was in- The waterbird counts in the Dutch Wadden itiated by the Ornithological Society Schleswig- Sea are part of the national monitoring program Holstein (OAG SH) in the 1960s; regular moni- of waterbirds in The Netherlands, which is a co- toring was jointly organized by the OAG SH operation between the Ministry of Agriculture, and the World Wide Fund for Nature (WWF) Nature and Food Quality, the Ministry of Water in 1987 and during the first period until 1994 Management and Public Works, Statistics The funded by the federal state Schleswig-Holstein Netherlands (CBS), Vogelbescherming Neder- and the Federal Ministry of Environment (Fed- land (BirdLife) and Sovon Dutch Centre for Field eral Environment Agency) as part of an ecosys- Ornithology, co-ordinated by Sovon. The aerial tem research project. Since then it was funded surveys of Common Eider were carried out un- by the National Park Administration Schleswig- der the responsibility of the Ministry of Water Holstein Wadden Sea. The coordination of the Management and Public Works. Additional, an- project moved from WWF to the Schutzstation nual surveys by boats of moulting Shelducks are Wattenmeer e.V. in 2004. The aerial surveys of organized and carried out by volunteers in coop- Common Eider and Shelduck were separately eration with the WaddenUnit of the Ministry of financed by the National Park Administration Agriculture, Nature and Food Quality.

Photo: Klaus Günther

Migratory bird trends until 2016/2017

3 Overview trends

Table 3.1 Long-term 30-years trend Short-term 10-year trend Trends until 2016/2017 - The whole 30 and last 10 years 1987/1988 - 2016/2017 2007/2008 - 2016/2017 Species time period. The species WS DK SH Nds/ NL WS DK SH Nds/ NL names in the table are sorted according to the HH HH Euring Code. Great Cormorant      Eurasian Spoonbill    Barnacle Goose         Brent Goose         Common Shelduck           Eurasian Wigeon          

Common Teal        

Mallard         

Northern Pintail           Northern Shoveler          Common Eider (25y trend)         Eurasian Oystercatcher           Pied Avocet           Great Ringed Plover           Kentish Plover       European Golden Plover       Grey Plover           Northern Lapwing           Red Knot         Sanderling          Curlew Sandpiper     Dunlin           Ruff        

Bar-tailed Godwit         

Whimbrel       

Eurasian Curlew         

Spotted Redshank           Common Redshank           Common Greenshank        Ruddy Turnstone          C. Black-headed Gull           Common Gull         European Herring Gull           Great Black-backed Gull         

strong increase strong decrease moderate increase moderate decrease stable uncertain WS - Wadden Sea; DK - Denmark; SH - Schleswig-Holstein; Nds/HH - Niedersachsen/Hamburg; NL - The Netherlands

Migratory bird trends until 2016/2017

3 Overview trends 9

Figure 3.1 Changes over 30 years (1987/1988 -2016/2017) in % (Common Eider since 1992/1993) Trend categories for the 30-year period for the -100 -75 -50 -25 0 25 50 75 100 International Wadden Sea Eurasian Spoonbill 2945 and the four countries, calculated with TrendSpotter Great Cormorant 566 on yearly estimates, ranked Barnacle Goose 545 after trend category and Sanderling value. Northern Pintail Northern Shoveler Great Ringed Plover Ruddy Turnstone Northern Lapwing Common Gull Grey Plover Bar-tailed Godwit strong increase Eurasian Curlew moderate increase Common Greenshank Curlew Sandpiper stable Common Teal trend not signi cant Black-headed Gull Common Shelduck moderate decrease Brent Goose strong decrease Dunlin Red Knot

European Golden Plover Common Redshank European Herring Gull Eurasian Wigeon

Whimbrel Pied Avocet Great Black-backed Gull Mallard

Spotted Redshank Eurasian Oystercatcher Kentish Plover Ruff

Migratory bird trends until 2016/2017

10 3 Overview trends

Figure 3.2 Trend categories for the Changes over recent 10 years (2007/2008-2016/20-17) in % 10-year period for the International Wadden Sea -100 -75 -50 -25 0 25 50 75 100 and the four countries, calculated with TrendSpotter Eurasian Spoonbill 111315453 on yearly estimates, ranked Barnacle Goose after trend category and Northern Pintail value. Ruff Sanderling Northern Shoveler Common Teal Kentish Plover Great Ringed Plover Black-headed Gull European Golden Plover Common Shelduck strong increase Brent Goose Great Cormorant moderate increase Ruddy Turnstone stable Mew Gull Northern Lapwing trend not signi cant European Herring Gull moderate decrease Bar-tailed Godwit Eurasian Curlew strong decrease Red Knot Dunlin Common Greenshank Grey Plover Spotted Redshank Common Redshank Eurasian Wigeon Pied Avocet Whimbrel Eurasian Oystercatcher Mallard Common Eider Great Black-backed Gull Curlew Sandpiper

Migratory bird trends until 2016/2017

3 Overview trends 11

Figure 3.3 Proportion of flyway popula- Proportion of Flyway Population (2007/2008-2016/2017) in % tion with regard to esti- Species Number 0 10 20 30 40 50 60 70 80 90 100 mated numbers (Wetlands International 2018). Common Shelduck (280,411) Dark-bellied Brent Goose (198,679) Northern Pintail (54,293) Dunlin (946,726) Grey Plover (133,794)

Bar-tailed Godwit (314,750) Knot (325,188) Pied Avocet (45,099) Barnacle Goose (550,509) Eurasian Oystercatcher (371,704) Eurasian Spoonbill (6,573) Eurasian Curlew (278,109) Spotted Redshank (79,424) Eurasian Wigeon (406,460) Sanderling (51,538) Great Ringed Plover (50,945)

Common Eider (190,568) Common Black-headed Gull (527,642) Spotted Redshank (15,046) Eurasian Golden Plover (136,344) Northern Shoveler (9,072) Common Gull (190,751) Herring Gull (155,477) Common Teal (50,080) Ruddy Turnstone (11,055) Common Greenshank (23,869) Great Cormorant (22,221)

Curlew Sandpiper (11,127) Great Black-backed Gull (9,510) Mallard (117,083) Northern Lapwing (138,761) Kentish Plover (958) Whimbrel (3,507) Ruff (3,200)

Photo: Klaus Günther

Migratory bird trends until 2016/2017

12 3 Overview trends

In order to help to identify possible relationships feeding on shellfish decreased over the years, between the species’ trends and their ecological although since ten years the trend is more or traits, trends of single species were combined. less stable. The long-term trend for worm-eat- Each bird species has been allocated to each of ing birds is stable. The only omnivorous species, four different guilds, namely food, feeding habi- Greater Black-backed Gull, declined. tat, breeding and wintering grounds. The decisions for these allocations have not Feeding Habitat been clear-cut in all cases; in particular regarding Species utilizing beaches or salt marshes show a food or feeding habitat, the choice was to pick moderate increase, while species of the coastal those which represented the main food or feeding grasslands (European Golden Plover, Northern habitat, respectively. Lapwing, Ruff) and tidal areas show a stable For the combined indices the geometrical mean long-term trend, that becomes more uncertain of species-specific indices have been used. over the last few years. Results Breeding Range Arctic breeders as well as non-arctic breeders show a moderate increase.. Figure 3.4 Food Combined trends accord- In the long run species depending on fish and ing to food guilds, feeding Wintering Range plants showed a moderate increase, but over the habitat, breeding range and wintering range (see Table last four seasons the trend is uncertain. That is Birds wintering in Africa show a moderate in- A1.1 & A1.2, p62-63). Trends also the case for those feeding more or less op- creasing long-term trend. The trend for birds were aggregated by using portunistically on “other invertebrates” is, for wintering in Europe was stable for years and is the geometrical mean of slightly increasing in the last ten years. TrendSpotter trend lines of which the long-term trend is stable. Species single species within each category.

Indicator food Indicator feeding habitat 250 140 Shell sh (n = 4) Worms (n = 11) 120 200 Fish (n = 4) Other invertebrates (n = 8) 100 Plants (n = 6) Omnivorous (n = 1) 150 80

60 Index values

100 Index values Salt marsh (n = 7) 40 Tidal (n = 21) 50 Beach & offshore (n = 3) 20 Coastal grassland (n = 3)

0 0 7 0 3 6 9 2 5 8 1 4 7 0 3 6 9 2 5 8 1 4 8 9 9 9 9 0 0 0 1 1 98 99 99 99 99 00 00 00 01 01 19 19 19 19 19 20 20 20 20 20 1 1 1 1 1 2 2 2 2 2

Indicator breeding range Indicator wintering range 120 120 115 Arctic breeder (n = 13) Non-Arctic breeder (n = 21) 100 110 80 105 100 60 Index values Index values 95 40 Europe (n = 22) 90 Africa (n = 12) 20 85

80 0 7 0 3 6 9 2 5 8 1 4 7 0 3 6 9 2 5 8 1 4 8 9 9 9 9 0 0 0 1 1 98 99 99 99 99 00 00 00 01 01 19 19 1 9 19 19 20 20 20 20 20 1 1 1 1 1 2 2 2 2 2

Migratory bird trends until 2016/2017

4 Species accounts

Photo: Bo Lassen Christiansen

Migratory bird trends until 2016/2017

Photo: Klaus Günther

Migratory bird trends until 2016/2017

4 Species accounts 15

4.1 Great Cormorant

Phalacrocorax carbo 00720 DK: Skarv D: Kormoran NL: Aalscholver Figure 4.1.1-4.1.6 12,000 6,000 Trends of Great Cormorant 10,000 5,000 in the international Wad- den Sea (WS) and the 8,000 4,000 four regions 1987/1988- 3,000 6,000 2016/2017; dots represent 2,000 4,000 annual averages; trendline 1,000 calculated by Trendspotter 2,000 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Great Cormorant numbers increased remarkably in the Wadden Sea from the 1980s up until 2003 during all seasons, reflecting the increase in the breeding populations in Northern Europe. Since then this increase turned into a stable to uncertain trend, due do a trend break in the Netherlands and Denmark, while in Schleswig-Holstein and Niedersachsen/Hamburg trends are stable since.

2,500 2,500 2,000 2,000

1,500 1,500

1,000 1,000 500 500 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

2,500 6,000 2,000 5,000 4,000 1,500 3,000 1,000 2,000 500 1,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Great Cormorant in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 30,000 Figure 4.1.7 2016/17 2016/17 Absolute numbers of Great 24,000 Cormorant in the interna- (A)/(B) International Wadden Sea   tional Wadden Sea and the (C) Denmark  18,000 four regions calculated by (D) Schleswig-Holstein   average of the 3 maximum 12,000 (E) Niedersachsen/Hamburg  numbers in the period 2007/2008-2016/2017. (F) The Netherlands   6,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

16 4 Species accounts

4.2 Eurasian Spoonbill

01440 Platalea leucorodia DK: Skestork D: Löffler NL: Lepelaar Figure 4.2.1.-4.2.6 3,000 1,500 Trends of Eurasian Spoonbill in the international Wad- 2,500 1,200 den Sea (WS) and the 2,000 four regions 1987/1988- 900 1,500 2016/2017; dots represent 600 annual averages; trendline 1,000 calculated by Trendspotter 300 500 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Since the 1980s the Eurasian Spoonbill shows a strong increase in the international Wadden Sea, which reflects the trends in all four Wadden Sea regions. The non-breeding numbers also reflect the growth of the breeding population the Wadden Sea. This Eurasian Spoonbill is both long and short term the species with the strongest increase.

150 1,000 120 800

90 600

60 400 30 200 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

1,000 1,500 800 1,200 600 900 400 600

200 300

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Eurasian Spoonbill in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines.

Figure 4.2.7 Area Period 1987/88 - 2007/08 - 10,000 Absolute numbers of Eura - 2016/17 2016/17 sian Spoonbill in the interna- 8,000 (A)/(B) International Wadden Sea tional Wadden Sea and the   (C) Denmark   6,000 four regions calculated by average of the 3 maximum (D) Schleswig-Holstein   numbers in the period (E) Niedersachsen/Hamburg   4,000 2007/2008-2016/2017. (F) The Netherlands   2,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 17

4.3 Barnacle Goose

Branta leucopsis 01670 DK: Bramgås D: Weißwangengans NL: Brandgans Figure 4.3.1-4.3.6 300,000 100,000 Trends of Barnacle Goose in 250,000 80,000 the international Wad- den Sea (WS) and the 200,000 60,000 four regions 1987/1988- 150,000 40,000 2016/2017; dots represent 100,000 annual averages; trendline 20,000 calculated by Trendspotter 50,000 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note The Barnacle Goose flyway population increased. This trend is clearly reflected by the numbers in the Wadden Sea. In all four Wadden Sea regions the increase is moderate to strong, although in recent years the trend development becomes unclear. Only Schleswig-Holstein still has increasing numbers of Barnacle Geese. Besides growing numbers of ‘barnacles’ in the winter season, the species also prolonged its staging period in spring, leaving for Acrtic breeding grounds in the end of May. The Barnacle Goose also settled and increased as a breeding bird in all Wadden Sea regions, with moulting sites throughout the Wadden Sea shores and islands.

100,000 100,000 80,000 80,000

60,000 60,000

40,000 40,000 20,000 20,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

100,000 100,000 80,000 80,000 60,000 60,000 40,000 40,000

20,000 20,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Barnacle Goose in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 600,000 Figure 4.3.7 2016/17 2016/17 Absolute numbers of Barnacle Goose in the inter- (A)/(B) International Wadden Sea   450,000 national Wadden Sea and (C) Denmark   the four regions calculated (D) Schleswig-Holstein   300,000 by average of the 3 maxi- (E) Niedersachsen/Hamburg   mum numbers in the period 150,000 2007/2008-2016/2017. (F) The Netherlands  

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

18 4 Species accounts

4.4 Dark-bellied Brent Goose

01680 Branta bernicla bernicla DK: Mørkbuget Knortegås D: Dunkelbäuchige Ringelgans NL: Rotgans Figure 4.4.1-4.4.6 100,000 50,000 Trends of Dark-bellied Brent Goose in the international 80,000 40,000 Wadden Sea (WS) and the 30,000 four regions 1987/1988- 60,000 2016/2017; dots represent 20,000 annual averages; trendline 40,000 10,000 calculated by Trendspotter 20,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Over 80% of the Dark-bellied Brent Goose flyway population can be found in the Wadden Sea. The long-term trend of the species in the international Wadden Sea is stable. Mainly Schleswig-Holstein showed an decrease in the early years, but the trend is quite stable for over twenty years now. Denmark and Niedersachsen both have slightly decreasing numbers, while in the Netherlands the overall trend is stable.

20,000 50,000 40,000 15,000 30,000 10,000 20,000 5,000 10,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

10,000 50,000 8,000 40,000 6,000 30,000 4,000 20,000

2,000 10,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Dark-bellied Brent Goose in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.4.7 Area Period 1987/88 - 2007/08 - 200,000 Absolute numbers of 2016/17 2016/17 Dark-bellied Brent Goose in (A)/(B) International Wadden Sea 150,000 the international Wadden   (C) Denmark Sea and the four regions calculated by average of (D) Schleswig-Holstein   100,000 the 3 maximum numbers (E) Niedersachsen/Hamburg   in the period 2007/2008- 50,000 (F) The Netherlands   2016/2017. strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 19

4.5 Common Shelduck

Tadorna tadorna 01730 DK: Gravand D: Brandgans NL: Bergeend Figure 4.5.1-4.5.6 200,000 100,000 Trends of CommonShel- 160,000 80,000 duck in the international Wadden Sea (WS) and the 60,000 120,000 four regions 1987/1988- 40,000 2016/2017; dots represent 80,000 annual averages; trendline 20,000 40,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Almost a 100% of the Common Shelduck flyway population uses the Wadden Sea, especially in the moulting period. Overall numbers on high tide roosts decreased up to the mid 1990´s; from then on slow fluctuations occur. Recent increases mostly in the Netherlands and less clear in Schleswig-Holstein combined with decreases in Nied- ersachsen/Hamburg and fluctuations in Denmark lead to an overall stable trend. The Common Shelduck moulting population used to have its main concentration in the Schleswig-Holstein Wadden Sea, but since the millennium the importance of the Dutch Wadden Sea for moulting Shelducks got bigger (Kleefstra & Kempf 2013). Since then numbers of moulting Shelducks in Schleswig-Holstein have continuously been decreasing up to 2009. The long-term trend is now increasing, but the short-term trend seems stable.

25,000 100,000 20,000 80,000

15,000 60,000

10,000 40,000 5,000 20,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

100,000 100,000 80,000 80,000 60,000 60,000 40,000 40,000

20,000 20,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Common Shelduck in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 300,000 Figure 4.5.7 2016/17 2016/17 Absolute numbers of Com- 250,000 mon Shelduck in the inter- (A)/(B) International Wadden Sea   national Wadden Sea and (C) Denmark   200,000 the four regions calculated (D) Schleswig-Holstein   150,000 by average of the 3 maximum numbers in the period (E) Niedersachsen/Hamburg   100,000 2007/2008-2016/2017. (F) The Netherlands   50,000 strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

20 4 Species accounts

4.6 Eurasian Wigeon

01790 Anas penelope DK: Pibeand D: Pfeifente NL: Smient Figure 4.6.1-4.6.6 200,000 100,000 Trends of Eurasian Wigeon in the international Wad- 160,000 80,000 den Sea (WS) and the 60,000 four regions 1987/1988- 120,000 2016/2017; dots represent 40,000 annual averages; trendline 80,000 20,000 calculated by Trendspotter 40,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note After increasing numbers of Wigeons in all regions of the Wadden Sea up to the mid 1990s the species shows a moderate decrease in all regions ever since. Only in Denmark the long-term trend is stable. The decrease in the Wadden Sea reflects international population changes, with Wigeons increasing on the northern latitude and decreasing numbers further south, in combination with a decreased breeding success in Fenno-Scandivian breeding areas (Fox et al. 2015).

30,000 100,000 25,000 80,000 20,000 60,000 15,000 40,000 10,000 5,000 20,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

30,000 60,000 25,000 50,000 20,000 40,000 15,000 30,000 10,000 20,000 5,000 10,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Eurasian Wigeon in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.6.7 Area Period 1987/88 - 2007/08 - 500,000 Absolute numbers of 2016/17 2016/17 Eurasian Wigeon in the in- 400,000 (A)/(B) International Wadden Sea ternational Wadden Sea and   (C) Denmark   300,000 the four regions calculated by average of the 3 maxi- (D) Schleswig-Holstein   200,000 mum numbers in the period (E) Niedersachsen/Hamburg   2007/2008-2016/2017. (F) The Netherlands   100,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 21

4.7 Common Teal

Anas crecca 01840 DK: Krikand D: Krickente NL: Wintertaling

30,000 10,000 Figure 4.7.1-4.7.6 Trends of Common Teal in 25,000 8,000 the international Wad- 20,000 6,000 den Sea (WS) and the 15,000 four regions 1987/1988- 4,000 2016/2017; dots represent 10,000 2,000 annual averages; trendline 5,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL ± 95 % confidence limits (dotted line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Only fractions of the large flyway population of theCommon Teal are counted in the Wadden Sea. Thus, trends in the Wadden Sea depend more on climate and habitat availability than on flyway trends. The flyway population is increasing, in the Wadden Sea the current trend, after a decrease up to the mid 1990s, is positive. Apart from Niedersachsen numbers were bigger in all regions since 2010.

10,000 10,000 8,000 8,000

6,000 6,000

4,000 4,000 2,000 2,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

10,000 10,000 8,000 8,000 6,000 6,000 4,000 4,000

2,000 2,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Common Teal in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines.

Area Period 1987/88 - 2007/08 - 60,000 Figure 4.7.7 2016/17 2016/17 Absolute numbers of 50,000 Common Teal in the interna- (A)/(B) International Wadden Sea   40,000 tional Wadden Sea and the (C) Denmark   four regions calculated by (D) Schleswig-Holstein   30,000 average of the 3 maximum (E) Niedersachsen/Hamburg numbers in the period  20,000 2007/2008-2016/2017. (F) The Netherlands  10,000 strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

22 4 Species accounts

4.8 Mallard

01860 Anas platyrhynchos DK: Gråand D: Stockente NL: Wilde Eend Figure 4.8.1-4.8.6 100,000 50,000 Trends of Mallard in the international Wadden Sea 80,000 40,000 (WS) and the four regions 30,000 1987/1988-2016/2017; dots 60,000 represent annual aver - 20,000 ages; trendline calculated 40,000 10,000 by Trendspotter (solid line) 20,000 together with the ± 95 % 0 confidence limits (dotted 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note The Mallard is counted in the Wadden Sea with less than 5% of its flyway populations. The overall trends are moderate but long-lasting decreases in the entire Wadden Sea. The short-term trend seems to be uncertain in all regions of the Wadden Sea.

10,000 50,000 8,000 40,000

6,000 30,000

4,000 20,000 2,000 10,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

50,000 50,000

40,000 40,000 30,000 30,000 20,000 20,000

10,000 10,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Mallard in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.8.7 Area Period 1987/88 - 2007/08 - 150,000 Absolute numbers of Mallard 2016/17 2016/17 in the international Wadden 120,000 (A)/(B) International Wadden Sea Sea and the four regions   (C) Denmark calculated by average of  90,000 the 3 maximum numbers (D) Schleswig-Holstein   60,000 in the period 2007/2008- (E) Niedersachsen/Hamburg   2016/2017. (F) The Netherlands   30,000 strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 23

4.9 Northern Pintail

Anas acuta 01890 DK: Spidsand D: Spießente NL: Pijlstaart Figure 4.9.1-4.9.6 50,000 10,000 Trends of Northern Pintail 40,000 8,000 in the international Wad- den Sea (WS) and the 6,000 30,000 four regions 1987/1988- 4,000 2016/2017; dots represent 20,000 annual averages; trendline 2,000 10,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note The proportion of the Northern Pintail population exceeds the 60% amply and numbers are clearly increasing. That seems to be the case for all regions, although the trend has become unclear in recent years. Annual averages for the Wadden Sea ran up from about 7600 on average during the 1980s and 1990s to about 16.000 on average since the millennium.

10,000 10,000 8,000 8,000

6,000 6,000

4,000 4,000 2,000 2,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

10,000 15,000 8,000 12,000 6,000 9,000 4,000 6,000

2,000 3,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Northern Pintail in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 60,000 Figure 4.9.7 2016/17 2016/17 Absolute numbers of Northern Pintail in the in- (A)/(B) International Wadden Sea 45,000   ternational Wadden Sea and (C) Denmark   the four regions calculated (D) Schleswig-Holstein   30,000 by average of the 3 maxi- (E) Niedersachsen/Hamburg   mum numbers in the period 15,000 2007/2008-2016/2017. (F) The Netherlands  

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

24 4 Species accounts

4.10 Northern Shoveler

01940 Anas clypeata DK: Skeand D: Löffelente NL: Slobeend Figure 4.10.1-4.10.6 5,000 2,000 Trends of Northern Shoveler in the international Wad- 4,000 1,600 den Sea (WS) and the four regions 1987/1988- 3,000 1,200 2016/2017; dots represent 800 annual averages; trendline 2,000 400 calculated by Trendspotter 1,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note The Wadden Sea represents some 20% of the flyway population of the Northern Shoveler. The species shows a moderate increase in the long run. This differs between the four Wadden Sea regions. The trend in Denmark is unclear, in Schleswig-Holstein increasing, in Niedersachsen stable, while the Northern Shoveler showed a strong increase in the Dutch Wadden Sea in recent years.

500 3,000 400 2,500 2,000 300 1,500 200 1,000 100 500 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

1,000 3,000 800 2,500 2,000 600 1,500 400 1,000 200 500 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Northern Shoveler in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.10.7 Area Period 1987/88 - 2007/08 - 10,000 Absolute numbers of 2016/17 2016/17 Northern Shoveler in the in- 8,000 (A)/(B) International Wadden Sea ternational Wadden Sea and   (C) Denmark  6,000 the four regions calculated by average of the 3 maxi- (D) Schleswig-Holstein   4,000 mum numbers in the period (E) Niedersachsen/Hamburg   2007/2008-2016/2017. (F) The Netherlands   2,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 25

4.11 Common Eider

Somateria mollissima 02060 DK: Ederfugl D: Eiderente NL: Eidereend Figure 4.11.1-4.11.6 400,000 150,000 Trends of Common Eider in 120,000 the international Wad- 300,000 den Sea (WS) and the 90,000 four regions 1987/1988- 200,000 60,000 2016/2017; dots represent annual averages; trendline 100,000 30,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Common Eider numbers counted from the airplane at mid winter (only since 1993) were stable in the Wadden Sea for the first years up to 1995/1996 and continuously decreased thereafter. Since 2005 numbers seem to stabilize overall. Especially counts in Niedersachsen/Hamburg were rather low in 2011- 2016 (except for 2015).

50,000 200,000 40,000 160,000 30,000 120,000 20,000 80,000 10,000 0 40,000 1985 1990 1995 2000 2005 2010 2015 2020 -10,000 0 1985 1990 1995 2000 2005 2010 2015 2020

100,000 200,000 80,000 160,000 60,000 120,000 40,000 80,000 20,000 0 40,000 1985 1990 1995 2000 2005 2010 2015 2020 -20,000 0 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Common Eider in the Wadden Sea Figures represent the trend 1992/1993 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.11.7 Area Period 1992/93 - 2007/08 - 200,000 2016/17 2016/17 Absolute numbers of Common Eider in the inter- (A)/(B) International Wadden Sea 150,000   national Wadden Sea and (C) Denmark  the four regions calculated 100,000 (D) Schleswig-Holstein  by average of the 3 maxi- (E) Niedersachsen/Hamburg   mum numbers in the period 50,000 2007/2008-2016/2017. (F) The Netherlands   Numbers are derived by strong increase strong decrease moderate increase    0 aerial counts. moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 26

4.12 Eurasian Oystercatcher

04500 Haematopus ostralegus DK: Strandskade D: Austernfischer NL: Scholekster Figure 4.12.1-4.12.6 600,000 250,000 Trends of Eurasian Oyster - catcher in the international 500,000 200,000 Wadden Sea (WS) and the 400,000 four regions 1987/1988- 150,000 300,000 2016/2017; dots represent 100,000 annual averages; trendline 200,000 calculated by Trendspotter 50,000 100,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note About 50% of the Eurasian Oystercatcher flyway population can be found in the Wadden Sea. Like the flyway population, the overall Wadden Sea numbers show a continuous and long-lasting moderate decrease. The decline is going on in all regions, apart from the Danish Wadden Sea, although numbers are much smaller there then in the other parts of the Wadden Sea. The development of maximum estimates in the Wadden Sea signs the decrease; 739,000 Oystercatchers in the period 1980-1991 (Meltofte et al. 1994), 582,000 for the period 1992-2000 (Blew et al. 2005) and 409,000 individuals for the period 2004-2014 (Blew et al. 2016).

30,000 150,000 25,000 120,000 20,000 90,000 15,000 60,000 10,000 5,000 30,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

200,000 250,000 160,000 200,000 120,000 150,000 80,000 100,000

40,000 50,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Eurasian Oystercatcher in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.12.7 Area Period 1987/88 - 2007/08 - 400,000 Absolute numbers of 2016/17 2016/17 Eurasian Oystercatcher in (A)/(B) International Wadden Sea 300,000 the international Wadden   (C) Denmark Sea and the four regions   calculated by average of (D) Schleswig-Holstein   200,000 the 3 maximum numbers (E) Niedersachsen/Hamburg   in the period 2007/2008- 100,000 (F) The Netherlands   2016/2017. strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 27

4.13 Pied Avocet

Recurvirostra avosetta 04560 DK: Klyde D: Säbelschnäbler NL: Kluut Figure 4.13.1-4.13.6 30,000 10,000 Trends of Pied Avocet in the 25,000 8,000 international Wadden Sea (WS) and the four regions 20,000 6,000 1987/1988-2016/2017; dots 15,000 4,000 represent annual aver- 10,000 ages; trendline calculated 2,000 by Trendspotter (solid line) 5,000 0 together with the ± 95 % 0 1985 1990 1995 2000 2005 2010 2015 2020 confidence limits (dotted 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Peak numbers of Pied Avocet during summer and autumn in the Wadden Sea contain almost 60% its flyway population. The overall Wadden Sea numbers show a continuous and long-lasting moderate decrease, which is going on in all Wadden Sea regions. Large numbers during the moulting period in the Danish and German Wadden Sea seem to be history. There seems to be a (slight) increase along the Dutch Wadden Sea coast in summer, but this does not seem to compensate the decline in Denmark and Germany and it is also not visible in the annual average numbers of Avocets in the Netherlands.

3,000 6,000 2,500 5,000 2,000 4,000 1,500 3,000 1,000 2,000 500 1,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

12,000 12,000 10,000 10,000 8,000 8,000 6,000 6,000 4,000 4,000 2,000 2,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Pied Avocet in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 50,000 Figure 4.13.7 2016/17 2016/17 Absolute numbers of Pied 40,000 Avocet in the international (A)/(B) International Wadden Sea   Wadden Sea and the four re- (C) Denmark   30,000 gions calculated by average (D) Schleswig-Holstein   of the 3 maximum numbers 20,000 (E) Niedersachsen/Hamburg   in the period 2007/2008- 2016/2017. (F) The Netherlands   10,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

28 4 Species accounts

4.14 Great Ringed Plover

04700 Charadrius hiaticula DK: Stor Præstekrave D: Sandregenpfeifer NL: Bontbekplevier Figure 4.14.1-4.14.6 15,000 5,000 Trends of Great Ringed Plover in the international 12,000 4,000 Wadden Sea (WS) and the four regions 1987/1988- 9,000 3,000 2016/2017; dots represent 2,000 annual averages; trendline 6,000 1,000 calculated by Trendspotter 3,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared Explanatory Note Already since the 1980s the Great Ringed Plover shows a moderate increase. This increase is mainly going on in the Wadden Sea regions of Schleswig-Holstein and the Netherlands. In the Danish Wadden Sea the trend is unclear, while in the Niedersachsen Wadden Sea numbers are decreasing. Three populations of Great Ringed Plover pass the Wadden Sea during migration; C.h. hiaticula is present form October to April, both Arctic breeding populations of C.h. tundra and C.h. psammodroma peak in May during spring migration.

1,000 6,000 800 5,000 4,000 600 3,000 400 2,000 200 1,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

4,000 6,000 5,000 3,000 4,000 2,000 3,000 2,000 1,000 1,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Great Ringed Plover in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.14.7 Area Period 1987/88 - 2007/08 - 60,000 Absolute numbers of 2016/17 2016/17 Great Ringed Plover in (A)/(B) International Wadden Sea 45,000 the international Wadden   (C) Denmark   Sea and the four regions calculated by average of (D) Schleswig-Holstein   30,000 the 3 maximum numbers (E) Niedersachsen/Hamburg   in the period 2007/2008- 15,000 (F) The Netherlands   2016/2017. strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 29

4.15 Kentish Plover

Charadrius alexandrinus 04770 DK: Hvidbrystet Præstekrave D: Seeregenpfeifer NL: Strandplevier Figure 4.15.1-4.15.6 1,000 250 Trends of Kentish Plover in 800 200 the international Wad- den Sea (WS) and the 150 600 four regions 1987/1988- 100 2016/2017; dots represent 400 annual averages; trendline 50 200 calculated by Trendspotter 0 (solid line) together with the 0 1980 1990 2000 2010 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note For the Kentish Plover, the Wadden Sea holds less than 1% of the entire flyway population, and overall very low numbers are registered during the synchronous counts. Both during spring and autumn these birds represent the local breeding population. Most trends in the overall Wadden Sea decreased during the 1980’s, but are unclear since then, apart from the Netherlands where the trend is plainly negative, what reflects the decline of the Kentish Plover as a breeding bird in the Dutch Wadden Sea.

30 300 25 250 20 200 15 150 10 100 5 50 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

800 70 60 600 50 40 400 30

200 20 10 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Kentish Plover in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 1,000 Figure 4.15.7 2016/17 2016/17 Absolute numbers of 800 Kentish Plover in the inter- (A)/(B) International Wadden Sea  national Wadden Sea and (C) Denmark  600 the four regions calculated (D) Schleswig-Holstein  by average of the 3 maxi- 400 (E) Niedersachsen/Hamburg  mum numbers in the period 2007/2008-2016/2017. (F) The Netherlands 200   strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

30 4 Species accounts

4.16 European Golden Plover

04850 Pluvialis apricaria DK: Hjejle D: Goldregenpfeifer NL: Goudplevier Figure 4.16.1-4.16.6 100,000 25,000 Trends of European Golden Plover in the international 80,000 20,000 Wadden Sea (WS) and the 15,000 four regions 1987/1988- 60,000 2016/2017; dots represent 10,000 annual averages; trendline 40,000 5,000 calculated by Trendspotter 20,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Of the European Golden Plover, three sub-populations may occur in the Wadden Sea, with the larg- est share belonging to the sub-population P. a. altifrons, which breeds in Northern Europe and winters in Central and Western Europe and North-West Africa. No method exists to distinguish Golder Plover populations during the counts (areas, counting month). Over 10% of the Golder Plover populations are covered by the coordinated counts in the Wadden Sea. The long-term trend over 30 years is stable, the short-term trend uncertain. This reflects the regional trends, except the Dutch trend, which seems stable for 30 years.

30,000 30,000 25,000 25,000 20,000 20,000 15,000 15,000 10,000 10,000 5,000 5,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

15,000 30,000 12,000 25,000 20,000 9,000 15,000 6,000 10,000 3,000 5,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for European Golden Plover in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.16.7 Area Period 1987/88 - 2007/08 - 150,000 Absolute numbers of 2016/17 2016/17 European Golden Plover in 120,000 (A)/(B) International Wadden Sea the international Wadden  (C) Denmark  90,000 Sea and the four regions calculated by average of (D) Schleswig-Holstein  60,000 the 3 maximum numbers (E) Niedersachsen/Hamburg  in the period 2007/2008- (F) The Netherlands   30,000 2016/2017. strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 31

4.17 Grey Plover

Pluvialis squatarola 04860 DK: Strandhjejle D: Kiebitzregenpfeifer NL: Zilverplevier Figure 4.17.1-4.17.6 100000 30,000 Trends of Grey Plover in the 25,000 80000 international Wadden Sea 20,000 (WS) and the four regions 60000 1987/1988-2016/2017; dots 15,000 represent annual aver- 40000 10,000 ages; trendline calculated 5,000 20000 by Trendspotter (solid line) 0 together with the ± 95 % 0 1985 1990 1995 2000 2005 2010 2015 2020 confidence limits (dotted 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Almost 60% of the total flyway population of Grey Plover uses the Wadden Sea outside the breeding season, thus the region is of high importance for the species. The total flyway population is reported with an uncertain decrease. In the Wadden Sea the overall trend had shown a short peak during the mid 1990s; afterwards a short decrease was followed by a stable period. Long-term stable trend increases are registered in the Netherlands and Denmark and moderate decreases in Niedersachsen/Hamburg and Schleswig-Holstein.

3,000 30,000 2,500 25,000 2,000 20,000 1,500 15,000 1,000 10,000 500 5,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

30,000 30,000 25,000 25,000 20,000 20,000 15,000 15,000 10,000 10,000 5,000 5,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Grey Plover in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines.

Area Period 1987/88 - 2007/08 - 150,000 Figure 4.17.7 2016/17 2016/17 Absolute numbers of Grey 120,000 Plover in the international (A)/(B) International Wadden Sea   Wadden Sea and the four re- (C) Denmark   90,000 gions calculated by average (D) Schleswig-Holstein   of the 3 maximum numbers (E) Niedersachsen/Hamburg   60,000 in the period 2007/2008- 2016/2017. (F) The Netherlands   30,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

32 4 Species accounts

4.18 Northern Lapwing

04930 Vanellus vanellus DK: Vibe D: Kiebitz NL: Kievit Figure 4.18.1-4.18.6 60,000 15,000 Trends of Northern Lapwing in the international Wad- 50,000 12,000 den Sea (WS) and the 40,000 four regions 1987/1988- 9,000 30,000 2016/2017; dots represent 6,000 annual averages; trendline 20,000 calculated by Trendspotter 3,000 10,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Only a small fraction of the Northern Lapwing flyway population uses the Wadden Sea. Like the flyway populations with an uncertain assessment of being stable, the Wadden Sea numbers show consider- able fluctuations, but the overall Wadden Sea trends are stable. Regional trends differ. In Denmark the long-term trend is stable, in Schleswig-Holstein increasing, in Niedersachsen decreasing and in the Netherlands increasing in 1980s en 1990s and stable since then.

10,000 25,000 8,000 20,000

6,000 15,000

4,000 10,000 2,000 5,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

20,000 20,000 16,000 16,000 12,000 12,000 8,000 8,000

4,000 4,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Northern Lapwing in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.18.7 Area Period 1987/88 - 2007/08 - 150,000 Absolute numbers of 2016/17 2016/17 Northern Lapwing in the in- 120,000 (A)/(B) International Wadden Sea ternational Wadden Sea and   (C) Denmark   90,000 the four regions calculated by average of the 3 maxi- (D) Schleswig-Holstein   60,000 mum numbers in the period (E) Niedersachsen/Hamburg   2007/2008-2016/2017. (F) The Netherlands  30,000  strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 33

4.19 Red Knot

Calidris canutus 04960 DK: Islandsk Ryle D: Knutt NL: Kanoetstrandloper Figure 4.19.1-4.19.6 300,000 150,000 Trends of Red Knot in the 250,000 120,000 international Wadden Sea (WS) and the four regions 200,000 90,000 1987/1988-2016/2017; dots 150,000 60,000 represent annual aver- 100,000 ages; trendline calculated 30,000 by Trendspotter (solid line) 50,000 0 together with the ± 95 % 0 1985 1990 1995 2000 2005 2010 2015 2020 confidence limits (dotted 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Large parts of both flyway populations of the Red Knot, the C. c. canutus migrating from Africa to Si- beria and the C. c. islandica wintering in the European regions and breeding in Greenland and Canada, use the Wadden Sea. The proportion is over 75% of the flyway population. The overall long-term trend is stable, where the decrease in Schleswig-Holstein is compensated by the increase in the Netherlands. The comparable lower numbers of the C. c. canutus population (counted in July and May) have an overall stable trend, but differ between Schleswig-Holstein and the Netherlands like the overall trend does. The high numbers of the C. c. islandica population (counted from September to April) are responsible for the overall trends.

60,000 150,000 50,000 120,000 40,000 90,000 30,000 60,000 20,000 10,000 30,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

20,000 150,000 16,000 120,000 12,000 90,000 8,000 60,000

4,000 30,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Red Knot in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.19.7 Area Period 1987/88 - 2007/08 - 400,000 2016/17 2016/17 Absolute numbers of Red Knot in the international (A)/(B) International Wadden Sea 300,000   Wadden Sea and the four re- (C) Denmark  gions calculated by average (D) Schleswig-Holstein   200,000 of the 3 maximum numbers (E) Niedersachsen/Hamburg  in the period 2007/2008- 100,000 2016/2017. (F) The Netherlands   strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

34 4 Species accounts

4.20 Sanderling

04970 Calidris alba DK: Sandløber D: Sanderling NL: Drieteenstrandloper Figure 4.20.1-4.20.6 15,000 Trends of Sanderling in the 25,000 international Wadden Sea 20,000 12,000 (WS) and the four regions 9,000 1987/1988-2016/2017; dots 15,000 represent annual aver - 6,000 ages; trendline calculated 10,000 3,000 by Trendspotter (solid line) 5,000 together with the ± 95 % 0 confidence limits (dotted 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Sanderling numbers are difficult to survey due to high peak numbers during a short time period in spring and summer. If the counts do not occur within this time window the numbers can vary greatly from year to year, as special Sanderling counts show in the western part of the Dutch Wadden Sea (Reneerkens et al. 2012). The overall trends in the Wadden Sea are increasing, mostly on account of results in the Netherlands. Trends are also positive in the Dannish Wadden Sea, but negative in Niedersachsen.

3,000 5,000 2,500 4,000 2,000 3,000 1,500 2,000 1,000 500 1,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

3,000 15,000

2,500 12,000 2,000 9,000 1,500 6,000 1,000 500 3,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands Trends for Sanderling in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.20.7 Area Period 1987/88 - 2007/08 - 60,000 Absolute numbers of 2016/17 2016/17 Sanderling in the interna- (A)/(B) International Wadden Sea 45,000 tional Wadden Sea and the   (C) Denmark four regions calculated by   average of the 3 maximum (D) Schleswig-Holstein  30,000 numbers in the period (E) Niedersachsen/Hamburg   2007/2008-2016/2017. 15,000 (F) The Netherlands  

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 35

4.21 Curlew Sandpiper

Calidris ferruginea 05090 DK: Krumnæbbet Ryle D: Sichelstrandläufer NL: Krombekstrandloper Figure 4.21.1-4.21.6 5,000 1,500 Trends of Curlew Sand- 4,000 1,200 piper in the international Wadden Sea (WS) and the 900 3,000 four regions 1987/1988- 600 2016/2017; dots represent 2,000 annual averages; trendline 300 1,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note The Curlew Sandpiper has a large flyway population of which only 1-2% visits the Wadden Sea during southbound migration. They migrate through the Wadden Sea in a very short period during July/August in a small number of sites, which makes them hard to count with the regular high tide roost counts. Schleswig-Holstein still has the biggest numbers, although numbers dropped since the millennium. Along the Frisian Wadden Sea coast of the Netherlands the number of Curlew Sandpipers increased and are almost comparable with Schleswig-Holstein numbers.

100 4,000 80 3,000 60 2,000 40 1,000 20 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

120 1,200 100 1,000 80 800 60 600 40 400 20 200 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Curlew Sandpiper in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 15,000 Figure 4.21.7 2016/17 2016/17 Absolute numbers of Curlew 12,000 Sandpiper in the interna- (A)/(B) International Wadden Sea  tional Wadden Sea and the (C) Denmark 9,000 four regions calculated by (D) Schleswig-Holstein  average of the 3 maximum 6,000 (E) Niedersachsen/Hamburg   numbers in the period 2007/2008-2016/2017. (F) The Netherlands 3,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

36 4 Species accounts

4.22 Dunlin

05120 Calidris alpina DK: Almindelig Ryle D: Alpenstrandläufer NL: Bonte Strandloper Figure 4.22.1-4.22.6 800,000 300,000 Trends of Dunlin in the international Wadden Sea 250,000 600,000 (WS) and the four regions 200,000 1987/1988-2016/2017; dots 150,000 represent annual aver - 400,000 ages; trendline calculated 100,000 by Trendspotter (solid line) 200,000 50,000 together with the ± 95 % 0 confidence limits (dotted 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note While the trends for the flyway populations of the nominate sub-species ofDunlin (C.c. alpina) is stable, estimates for the small populations of C.c. schinzii are uncertain. The overall long- and short-term trends in the Wadden Sea, where large numbers and most likely large proportions of about 70% of these flyway population are present during the yearly cycle, show moderate decreases. The decrease is going on the nortern part of the Wadden Sea (Denmark, Schleswig-Holstein), while in the southern part numbers are stable (Niedersachsen) to increasing (the Netherlands).

150,000 300,000 120,000 250,000 200,000 90,000 150,000 60,000 100,000 30,000 50,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

200,000 300,000 250,000 150,000 200,000 100,000 150,000 100,000 50,000 50,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Dunlin in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.22.7 Area Period 1987/88 - 2007/08 - 1,000,000 Absolute numbers of Dunlin 2016/17 2016/17 in the international Wadden 800,000 (A)/(B) International Wadden Sea Sea and the four regions   (C) Denmark   600,000 calculated by average of the 3 maximum numbers (D) Schleswig-Holstein   400,000 in the period 2007/2008- (E) Niedersachsen/Hamburg   2016/2017. (F) The Netherlands   200,000 strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 37

4.23 Ruff

Philomachus pugnax 05170 DK: Brushane D: Kampfläufer NL: Kemphaan Figure 4.23.1-4.23.6 6,000 1,500 Trends of Ruff in the 5,000 1,200 international Wadden Sea (WS) and the four regions 4,000 900 1987/1988-2016/2017; dots 3,000 600 represent annual aver- 2,000 ages; trendline calculated 300 by Trendspotter (solid line) 1,000 0 together with the ± 95 % 0 1985 1990 1995 2000 2005 2010 2015 2020 confidence limits (dotted 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Less than 1% of the Ruff flyway population migrates through the Wadden Sea. The flyway population trend is seriously decreasing. In the Wadden Sea the long-term trend is decreasing, but due to higher numbers in Schleswig-Holstein the short-term trend is positive.

3,000 2,500 2,400 2,000

1,800 1,500

1,200 1,000 600 500 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

500 500 400 400 300 300 200 200

100 100

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Ruff in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 5,000 Figure 4.23.7 2016/17 2016/17 Absolute numbers of Ruff in 4,000 the international Wadden (A)/(B) International Wadden Sea   Sea and the four regions (C) Denmark   3,000 calculated by average of (D) Schleswig-Holstein   the 3 maximum numbers 2,000 (E) Niedersachsen/Hamburg in the period 2007/2008- 2016/2017. (F) The Netherlands 1,000   strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

38 4 Species accounts

4.24 Bar-tailed Godwit

05340 Limosa lapponica DK: Lille Kobbersneppe D: Pfuhlschnepfe NL: Rosse Grutto Figure 4.24.1-4.24.6 80,000 Trends of Bar-tailed Godwit 120,000 in the international Wadden 100,000 Sea (WS) and the four 60,000 80,000 regions 1987/1988- 40,000 2016/2017; dots represent 60,000 annual averages; trendline 40,000 20,000 calculated by Trendspotter 20,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Two populations of the Bar-tailed Godwit migrate through the Wadden Sea, both with comparable numbers; the nominate sub-species L. l. lapponica breeds in high arctic Scandinavia and Northern Russia, and winters in coastal Western Europe and North-West Africa. It is present in the Wadden Sea most of the year from September to April, from which counts apply. The flyway population counts 120,000 individuals and its trend is stable. The L. l. taymyrensis breeds in Western and Central Siberia and winters in coastal West and South-West Africa; individuals of this population will migrate through the Wadden Sea in May and return during July and August. The flyway population counts 500,000 individuals and its trend is an uncertain decrease. Overall numbers in the Wadden Sea are stable. In the German parts of the Wadden Sea the Bar-tailed Godwit shows a decline, while the species increased in the Dutch Wadden Sea during the 1980s and 1990s and numbers are stable since then.

15,000 50,000 12,000 40,000

9,000 30,000

6,000 20,000 3,000 10,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

15,000 100,000 12,000 80,000 9,000 60,000 6,000 40,000

3,000 20,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Bar-tailed Godwit in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.24.7 Area Period 1987/88 - 2007/08 - 400,000 Absolute numbers of 2016/17 2016/17 Bar-tailed Godwit in the in- (A)/(B) International Wadden Sea 300,000 ternational Wadden Sea and   (C) Denmark  the four regions calculated by average of the 3 maxi- (D) Schleswig-Holstein   200,000 mum numbers in the period (E) Niedersachsen/Hamburg   2007/2008-2016/2017. 100,000 (F) The Netherlands   strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 39

4.25 Whimbrel

Numenius phaeopus 05380 DK: Lille Regnspove D: Regenbrachvogel NL: Regenwulp Figure 4.25.1-4.25.6 1,500 500 Trends of Whimbrel in the 1,200 400 international Wadden Sea (WS) and the four regions 300 900 1987/1988-2016/2017; dots 200 represent annual aver- 600 ages; trendline calculated 100 300 by Trendspotter (solid line) 0 together with the ± 95 % 0 1985 1990 1995 2000 2005 2010 2015 2020 confidence limits (dotted 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Only 1-2% of the stable Whimbrel flyway population is counted in the Wadden Sea region. Numbers are hard to monitor, because spring migration peaks shortly in the end of April. Long- and short-term trends are currently stable in the Wadden Sea, but fluctuating. In Denmark numbers have been very low during the last decade and lead to a decreasing trend. In all other parts short-term trends are uncertain.

200 500 160 400

120 300

80 200 40 100 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

1,000 1,000 800 800 600 600 400 400

200 200

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Whimbrel in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 5,000 Figure 4.25.7 2016/17 2016/17 Absolute numbers of 4,000 Whimbrel in the interna- (A)/(B) International Wadden Sea   tional Wadden Sea and the (C) Denmark  3,000  four regions calculated by (D) Schleswig-Holstein   average of the 3 maximum 2,000 (E) Niedersachsen/Hamburg numbers in the period 2007/2008-2016/2017. (F) The Netherlands  1,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

40 4 Species accounts

4.26 Eurasian Curlew

05410 Numenius arquata DK: Stor Regnspove D: Großer Brachvogel NL: Wulp Figure 4.26.1-4.26.6 250,000 100,000 Trends of Eurasian Curlew in the international Wad- 200,000 80,000 den Sea (WS) and the 60,000 four regions 1987/1988- 150,000 2016/2017; dots represent 40,000 annual averages; trendline 100,000 20,000 calculated by Trendspotter 50,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note The Eurasian Curlew flyway population is seriously decreasing. However, the Wadden Sea population, representing some 35-40% of the flyway population, is stable both in the long- and short-term trends; particularly the last 10 years, estimates in all regions have not changed but stabilised at one level. Of these regions Niedersachsen and the Netherlands hold the biggest numbers by far and in both parts of the Wadden Sea numbers are stable over a thirty year period.

10,000 50,000 8,000 40,000

6,000 30,000

4,000 20,000 2,000 10,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

100,000 150,000 80,000 120,000 60,000 90,000 40,000 60,000

20,000 30,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Eurasian Curlew in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines.

Figure 4.26.7 Area Period 1987/88 - 2007/08 - 300,000 Absolute numbers of 2016/17 2016/17 Eurasian Curlew in the in- (A)/(B) International Wadden Sea 240,000 ternational Wadden Sea and   the four regions calculated (C) Denmark  180,000 by average of the 3 maxi - (D) Schleswig-Holstein   mum numbers in the period (E) Niedersachsen/Hamburg   120,000 2007/2008-2016/2017. (F) The Netherlands   60,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 41

4.27 Spotted Redshank

Tringa erythropus 05450 DK: Sortklire D: Dunkler Wasserläufer NL: Zwarte Ruiter Figure 4.27.1-4.27.6 10,000 5,000 Trends of Spotted Red- 8,000 4,000 shank in the international Wadden Sea (WS) and the 3,000 6,000 four regions 1987/1988- 2,000 2016/2017; dots represent 4,000 annual averages; trendline 1,000 2,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared Explanatory Note The Spotted Redshank is difficult to monitor due to its short passage time period, with large numbers at only a few sites. Wadden Sea numbers represent about 20% of the flyway population which is assessed to be stable, however with some uncertainty. The overall Wadden Sea was decreasing on the long-term, but seems to stabilize in the short-term. This reflects the trend in Schleswig-Holstein. In the Dutch Wad- den Sea the trend of the Spotted Redshank is negative over the whole thirty year period.

1,000 5,000 800 4,000

600 3,000 400 2,000 200 1,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

2,000 5,000 1,600 4,000 1,200 3,000 800 2,000

400 1,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Spotted Redshank in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines.

Area Period 1987/88 - 2007/08 - 20,000 Figure 4.27.7 2016/17 2016/17 Absolute numbers of Spotted Redshank in the interna- (A)/(B) International Wadden Sea 16,000   tional Wadden Sea and the (C) Denmark   12,000 four regions calculated by (D) Schleswig-Holstein   average of the 3 maximum (E) Niedersachsen/Hamburg   8,000 numbers in the period 2007/2008-2016/2017. (F) The Netherlands   4,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

42 4 Species accounts

4.28 Common Redshank

05460 Tringa totanus DK: Rødben D: Rotschenkel NL: Tureluur Figure 4.28.1-4.28.6 50,000 20,000 Trends of Common Red - shank in the international 40,000 16,000 Wadden Sea (WS) and the 12,000 four regions 1987/1988- 30,000 2016/2017; dots represent 8,000 annual averages; trendline 20,000 4,000 calculated by Trendspotter 10,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note The Common Redshank occurs in the Wadden Sea with three populations, thus numbers and trends are not easy to assess in relation to the respective flyway populations. The overall Wadden Sea long-term trend is moderate decreasing, due to declining numbers in the German parts of the Wadden Sea. In both the Danish and Dutch Wadden Sea numbers of Common Redshanks are stable.

3,000 15,000 2,500 12,000 2,000 9,000 1,500 6,000 1,000 500 3,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

15,000 25,000 12,000 20,000 9,000 15,000 6,000 10,000

3,000 5,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Common Redshank in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.28.7 Area Period 1987/88 - 2007/08 - 100,000 Absolute numbers of 2016/17 2016/17 Common Redshank in the in- 80,000 (A)/(B) International Wadden Sea ternational Wadden Sea and   (C) Denmark   60,000 the four regions calculated by average of the 3 maxi- (D) Schleswig-Holstein   40,000 mum numbers in the period (E) Niedersachsen/Hamburg   2007/2008-2016/2017. (F) The Netherlands   20,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 43

4.29 Common Greenshank

Tringa nebularia 05480 DK: Hvidklire D: Grünschenkel NL: Groenpootruiter Figure 4.29.1-4.29.6 10,000 2,500 Trends of Common Green- 8,000 2,000 shank in the international Wadden Sea (WS) and the 1,500 6,000 four regions 1987/1988- 1,000 2016/2017; dots represent 4,000 annual averages; trendline 500 2,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note The Wadden Sea plays a minor role for the Common Greenshanks with only some 10% of the stable flyway population staging during autumn, and fewer during spring. The overall trend in the Wadden Sea is stable, yet fluctuating largely in low numbers. Trends differ between regions. In Denmark Common Greenshanks increased in the 1980s and early 1990s, but the short-term trend is unclear. Same goes for the short-term trends in Schleswig-Holstein and the Netherlands, where numbers used to be stable. In Niedersachsen numbers are stable over the whole thirty year period.

2,000 2,500 1,600 2,000

1,200 1,500

800 1,000 400 500 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

2,000 5,000 1,600 4,000 1,200 3,000 800 2,000

400 1,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Common Greenshank in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 30,000 Figure 4.29.7 2016/17 2016/17 Absolute numbers of 24,000 Common Greenshank in (A)/(B) International Wadden Sea   the international Wadden (C) Denmark  18,000 Sea and the four regions (D) Schleswig-Holstein  calculated by average of 12,000 (E) Niedersachsen/Hamburg   the 3 maximum numbers in the period 2007/2008- (F) The Netherlands  6,000 2016/2017. strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

44 4 Species accounts

4.30 Ruddy Turnstone

05610 Arenaria interpres DK: Stenvender D: Steinwälzer NL: Steenloper Figure 4.30.1-4.30.6 10,000 5,000 Trends of Ruddy Turn - stone in the international 8,000 4,000 Wadden Sea (WS) and the 3,000 four regions 1987/1988- 6,000 2016/2017; dots represent 2,000 annual averages; trendline 4,000 1,000 calculated by Trendspotter 2,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Two populations of Ruddy Turnstone pass the Wadden Sea on migration. One population, breeds in Canada and Greenland and winters in Western Europe and North-West Africa and is present in the Wadden Sea most of the year from August to April; this flyway population is assessed to be increasing. The other population breeds in Fennoscandia and North-West Russia and winters in Africa, and passes the Wadden Sea mainly during July and May; it is decreasing. The overall Wadden Sea trend for this species is stable in the long-term, despite big fluctuations, dominated by the numbers of Ruddy Turnstones in the Dutch part of the Wadden Sea. During the last 10 years the trend is uncertain. While the number of Ruddy Turnstones increased in Niedersachsen/Hamburg over some 20 years, numbers in Denmark are decreasing. Coverage of this species by the Trilateral Monitoring Program is generally poor and low numbers, in particular in Denmark, are registered.

500 1,500 400 1,200

300 900

200 600 100 300 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

2,500 5,000 2,000 4,000 1,500 3,000 1,000 2,000

500 1,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Ruddy Turnstone in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.30.7 Area Period 1987/88 - 2007/08 - 15,000 Absolute numbers of Ruddy 2016/17 2016/17 Turnstone in the interna- 12,000 (A)/(B) International Wadden Sea tional Wadden Sea and the   (C) Denmark   9,000 four regions calculated by average of the 3 maximum (D) Schleswig-Holstein   6,000 numbers in the period (E) Niedersachsen/Hamburg   2007/2008-2016/2017. (F) The Netherlands  3,000 strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 45

4.31 Common Black-headed Gull

Larus ridibundus 05820 DK: Hættemåge D: Lachmöwe NL: Kokmeeuw Figure 4.31.1-4.31.6 250,000 100,000 Trends of Common Black- 200,000 80,000 headed Gull in the international Wadden Sea (WS) and 60,000 150,000 the four regions 1987/1988- 40,000 2016/2017; dots represent 100,000 annual averages; trendline 20,000 50,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Some 10-15% of the Black-headed Gull flyway population use the Wadden Sea. The Trilateral counts only cover a part of the numbers actually using the Wadden Sea, because many birds occur offshore, inland, at harbours or rubbish dumps. However, for the 20-25 % of the flyway population present in the Wadden Sea, the trend is stable in the long-term trend, but uncertain in the short-term trend. For Denmark the long-term trend shows a slight decrease, while numbers in the German parts of the Wad- den Sea increase. In The Netherlands the long-term trend is stable.

20,000 100,000 16,000 80,000

12,000 60,000

8,000 40,000 4,000 20,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

100,000 150,000 80,000 120,000 60,000 90,000 40,000 60,000

20,000 30,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Common Black-headed Gull in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 600,000 Figure 4.31.7 2016/17 2016/17 Absolute numbers of Common Black-headed Gull (A)/(B) International Wadden Sea 450,000   in the international Wadden (C) Denmark   Sea and the four regions (D) Schleswig-Holstein   300,000 calculated by average of (E) Niedersachsen/Hamburg   the 3 maximum numbers 150,000 in the period 2007/2008- (F) The Netherlands   2016/2017. strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

46 4 Species accounts

4.32 Common Gull

05900 Larus canus DK: Stormmåge D: Sturmmöwe NL: Stormmeeuw Figure 4.32.1-4.32.6 150,000 50,000 Trends of Common Gull in the international Wad- 120,000 40,000 den Sea (WS) and the 30,000 four regions 1987/1988- 90,000 2016/2017; dots represent 20,000 annual averages; trendline 60,000 10,000 calculated by Trendspotter 30,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Over 10% of the Common Gull flyway population uses the Wadden Sea, however, many of them feed inland and only rest in the Wadden Sea during night. The overall long-term trend is stable for the Wad- den Sea, but uncertain for the short-term. Thisis the samen for Niedersachsen/Hamburg and the Neth- erlands. Denmark shows a slight decrease, whereas numbers in Schleswig-Holstein are stable.

20,000 25,000 16,000 20,000

12,000 15,000

8,000 10,000 4,000 5,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

50,000 100,000 40,000 80,000 30,000 60,000 20,000 40,000

10,000 20,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Common Gull in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.32.7 Area Period 1987/88 - 2007/08 - 200,000 Absolute numbers of 2016/17 2016/17 Common Gull in the interna- 160,000 (A)/(B) International Wadden Sea tional Wadden Sea and the   (C) Denmark four regions calculated by   120,000 average of the 3 maximum (D) Schleswig-Holstein   80,000 numbers in the period (E) Niedersachsen/Hamburg  2007/2008-2016/2017. (F) The Netherlands  40,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 47

4.33 Herring Gull

Larus argentatus 05920 DK: Sølvmåge D: Silbermöwe NL: Zilvermeeuw Figure 4.33.1-4.33.6 200,000 100,000 Trends of Herring Gull in the 160,000 80,000 international Wadden Sea (WS) and the four regions 60,000 120,000 1987/1988-2016/2017; dots 40,000 represent annual aver- 80,000 ages; trendline calculated 20,000 40,000 by Trendspotter (solid line) 0 together with the ± 95 % 0 1985 1990 1995 2000 2005 2010 2015 2020 confidence limits (dotted 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL line).

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Less than 10% of the Herring Gull flyway population is registered in the Wadden Sea, however many birds are not covered because birds either feed offshore or inland. The species showed a moderate decrease over the years, but numbers seem to stabilize. The decrease took place in the whole international Wadden Sea, apart from Denmark, where the Herring Gull increased and number became even bigger than in the German parts of the Wadden Sea.

50,000 50,000 40,000 40,000

30,000 30,000

20,000 20,000 10,000 10,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

50,000 100,000 40,000 80,000 30,000 60,000 20,000 40,000

10,000 20,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Herring Gull in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 200,000 Figure 4.33.7 2016/17 2016/17 Absolute numbers of Herring 160,000 Gull in the international (A)/(B) International Wadden Sea   Wadden Sea and the four re- (C) Denmark   120,000 gions calculated by average (D) Schleswig-Holstein   of the 3 maximum numbers 80,000 (E) Niedersachsen/Hamburg   in the period 2007/2008- 2016/2017. (F) The Netherlands   40,000

strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

4 Species accounts 48

4.34 Great Black-backed Gull

06000 Larus marinus DK: Svartbag D: Mantelmöwe NL: Grote Mantelmeeuw Figure 4.34.1-4.34.6 10,000 5,000 Trends of Great Black-backed Gull in the international 8,000 4,000 Wadden Sea (WS) and the 3,000 four regions 1987/1988- 6,000 2016/2017; dots represent 2,000 annual averages; trendline 4,000 1,000 calculated by Trendspotter 2,000 (solid line) together with the 0 ± 95 % confidence limits 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 (dotted line). Trend DK Trend SH Trend NS Trend NL

(A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Only a small fraction of the Great Black-backed Gulls flyway population is counted in the Wadden Sea, since many birds use harbours and offshore areas. Apart from some peak numbers in the mid 1990s, mainly caused by trends in Denmark and the Netherlands, the numbers of Great Black-backed Gulls declined up to 2005 and are more or less stable since then.

2,000 2,500 1,600 2,000

1,200 1,500

800 1,000 400 500 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

1,500 10,000 1,200 8,000 900 6,000 600 4,000

300 2,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Great Black-backed Gull in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from all months to express an overall trend for the entire year. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Figure 4.34.7 Area Period 1987/88 - 2007/08 - 10,000 Absolute numbers of Great 2016/17 2016/17 Black-backed Gull in the in- 8,000 (A)/(B) International Wadden Sea ternational Wadden Sea and   (C) Denmark   6,000 the four regions calculated by average of the 3 maxi- (D) Schleswig-Holstein   4,000 mum numbers in the period (E) Niedersachsen/Hamburg   2007/2008-2016/2017. (F) The Netherlands  2,000 strong increase strong decrease moderate increase    0 moderate decrease stable uncertain WS DK SH Nds/HH NL

Migratory bird trends until 2016/2017

5 Subspecies accounts

Table 5.1 Long-term 30-years trend Short-term 10-year trend Trends until 2016/2017 - The 1987/1988 - 2016/2017 2007/2008 - 2016/2017 whole 30 and last 10 years Species WS DK SH Nds/ NL WS DK SH Nds/ NL time period. The species names in the table are HH HH sorted according to the Great Ringed Plover Euring Code. (hiaticula)        Great Ringed Plover (psammodroma/tundrae)          Red Knot (canutus)          

Red Knot      (islandica)     Bar-tailed Godwit (taymyrensis)         

Bar-tailed Godwit          (lapponica) Common Redshank (totanus)          

Common Redshank      (robusta)    Ruddy Turnstone (Greenland & NE Canada)        

Ruddy Turnstone (Scandi-          navia - Western Russia)

strong increase strong decrease moderate increase moderate decrease stable uncertain      WS - Wadden Sea; DK - Denmark; SH - Schleswig-Holstein; Nds/HH - Niedersachsen/Hamburg; NL - The Netherlands

Migratory bird trends until 2016/2017

50 5 Subspecies accounts

5.1 Great Ringed Plover (hiaticula)

04701 Charadrius hiaticula hiaticula DK: Stor Præstekrave D: Sandregenpfeifer NL: Bontbekplevier Figure 5.1.1-5.1.6 1,500 500 Trends of subspecies Great Ringed 1,200 400 Plover(hiaticula) in the 300 international Wadden Sea 900 (WS) and the four regions 200 1987/1988-2016/2017; dots 600 100 represent annual aver - 300 ages; trendline calculated 0 by Trendspotter (solid line) 0 1985 1990 1995 2000 2005 2010 2015 2020 together with the ± 95 % 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL confidence limits (dotted line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note The rather low numbers of nominate sub-species C.h.hiaticula (counts from October to April) show a moderate decrease, mainly caused by the negative trend in Niedersachsen/Hamburg. In the Netherlands the sub-species is decreasing since the millennium.

100 1,000 1,000 80 800 800

60 600 600

40 400 400 20 200 200 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

1,000 1,000 800 800 600 600 400 400

200 200

0 0 2020 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Great Ringed Plover (hiaticula) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea   (C) Denmark

(D) Schleswig-Holstein   (E) Niedersachsen/Hamburg   (F) The Netherlands 

strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

5 Subspecies accounts 51

5.2 Great Ringed Plover (psammodroma/tundrae )

Charadrius hiaticula psammodroma/tundrae 04702 DK: Stor Præstekrave D: Sandregenpfeifer NL: Bontbekplevier Figure 5.2.2-5.2.6 15,000 5,000 Trends of subspecies Great Ringed Plover (psammodro- 12,000 4,000 ma/tundrae) in the interna- 3,000 9,000 tional Wadden Sea (WS) and 2,000 the four regions 1987/1988- 6,000 2016/2017; dots represent 1,000 3,000 annual averages; trendline 0 calculated by Trendspotter 0 2020 1985 1990 1995 2000 2005 2010 2015 2020 (solid line) together with the 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL ± 95 % confidence limits (dotted line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Large numbers of both the arctic breeding C. h. tundrae and C. h. psammodroma pass through during May and from July to September also. Highest numbers occur in Schleswig-Holstein and the Nether- lands, where numbers are still increasing. The overall trend is positive, both long- and short-term.

500 5,000 400 4,000

300 3,000

200 2,000 100 1,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

2,500 5,000 20,000 2,000 4,000 16,000 1,500 3,000 12,000 1,000 2,000 8,000

500 1,000 4,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Great Ringed Plover (psammodroma/tundrae) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea   (C) Denmark  (D) Schleswig-Holstein   (E) Niedersachsen/Hamburg   (F) The Netherlands  

strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

52 5 Subspecies accounts

5.3 Red Knot (canutus)

04961 Calidris canutus canutus DK: Islandsk Ryle D: Knutt NL: Kanoetstrandloper Figure 5.3.1-5.3.6 20,000 Trends of subspecies Red 50,000 Knot (canutus) in the 40,000 16,000 international Wadden Sea 12,000 (WS) and the four regions 30,000 1987/1988-2016/2017; dots 8,000 represent annual aver- 20,000 4,000 ages; trendline calculated 10,000 by Trendspotter (solid line) 0 together with the ± 95 % 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 confidence limits (dotted Trend DK Trend SH Trend NS Trend NL line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Red Knots of the sub-species C. c. canutus migrating from Africa to Siberia are mainly present in the Wadden Sea in May and July-August. The overall trend is stable, although in Schleswig-Holstein a continuous decrease occurs since the late 1990’s, which is compensated by the increase in the Danish and Dutch Wadden Sea. Something similar is going on with the other sub-species C. c. islandica.

20,000 30,000 16,000 25,000 20,000 12,000 15,000 8,000 10,000 4,000 5,000 0 0 2020 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

10,000 10,000

8,000 8,000 6,000 6,000 4,000 4,000

2,000 2,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Red Knot (canutus) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea   (C) Denmark   (D) Schleswig-Holstein   (E) Niedersachsen/Hamburg   (F) The Netherlands   strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

5 Subspecies accounts 53

5.4 Red Knot (islandica)

Calidris canutus islandica 04962 DK: Islandsk Ryle D: Knutt NL: Kanoetstrandloper Figure 5.4.1-5.4.6 250,000 150,000 100,000 Trends of subspecies Red 200,000 120,000 80,000 Knot (islandica) in the international Wadden Sea 90,000 150,000 60,000 (WS) and the four regions 60,000 1987/1988-2016/2017; dots 100,000 40,000 represent annual aver- 30,000 50,000 20,000 ages; trendline calculated 0 by Trendspotter (solid line) 0 1985 1990 1995 2000 2005 2010 2015 2020 together with the ± 95 % 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL confidence limits (dotted line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Birds of the subspecies C. c. islandica winter in the European region and breed in Greenland and Canada. In comparison with the C. c. canutus subspecies the overall trend of C. c. islandica uncertain for the short-term. The sub-species shows a strong decrease in Schleswig-Holstein, but numbers in Denmark and the Netherlands got bigger through the years.

50,000 150,000 40,000 120,000

30,000 90,000

20,000 60,000 10,000 30,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

15,000 100,000 10,000 12,000 80,000 8,000 9,000 60,000 6,000 6,000 40,000 4,000

3,000 20,000 2,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Red Knot (islandica) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea   (C) Denmark  (D) Schleswig-Holstein   (E) Niedersachsen/Hamburg   (F) The Netherlands   strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

54 5 Subspecies accounts

5.5 Bar-tailed Godwit (taymyrensis)

05341 Limosa lapponica taymyrensis DK: Lille Kobbersneppe D: Pfuhlschnepfe NL: Rosse Grutto Figure 5.5.1-5.5.6 100,000 25,000 Trends of subspecies Bar- tailed Godwit (taymyrensis 80,000 20,000 in the international Wadden 15,000 Sea (WS) and the four 60,000 regions 1987/1988- 10,000 2016/2017; dots represent 40,000 5,000 annual averages; trendline 20,000 calculated by Trendspotter 0 (solid line) together with the 2020 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits Trend DK Trend SH Trend NS Trend NL (dotted line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Birds of the Siberian subspecies L. l. taymyrensis are mainly present in the Wadden Sea in May and in July/August. The overall trend is stable, but different in the sub regions. Most birds occur in the Neth- erlands, where numbers increased until the mid 1990’s and remained stable since then. In opposite a continuous decrease occurred in the German parts of the Wadden Sea.

10,000 25,000 8,000 20,000

6,000 15,000

4,000 10,000 2,000 5,000 0 0 2020 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

10,000 50,000 8,000 40,000 6,000 30,000 4,000 20,000

2,000 10,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Bar-tailed Godwit (taymyrensis) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea   (C) Denmark  (D) Schleswig-Holstein   (E) Niedersachsen/Hamburg   (F) The Netherlands   strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

5 Subspecies accounts 55

5.6 Bar-tailed Godwit (lapponica)

Limosa lapponica lapponica 05342 DK: Lille Kobbersneppe D: Pfuhlschnepfe NL: Rosse Grutto Figure 5.6.1-5.6.6 100,000 50,000 Trends of subspecies Bar- 80,000 40,000 tailed Godwit (lapponica) in the international Wadden 30,000 60,000 Sea (WS) and the four 20,000 regions 1987/1988- 40,000 2016/2017; dots represent 10,000 20,000 annual averages; trendline 0 calculated by Trendspotter 0 1985 1990 1995 2000 2005 2010 2015 2020 (solid line) together with the 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL ± 95 % confidence limits (dotted line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Birds of the subspecies L. l. lapponica breed in northern Scandinavia and northern Russia and winter in coastal Western Europe and North-West Africa. From Septmber to April all birds in the Wadden Sea are supposed to belong to this subspecies. The overall trend of these wintering birds is stable. Also for this sub-species the biggest numbers are found in the Dutch Wadden Sea, where the L. l. lapponica is increasing. Schleswig-Holstein shows an opposite trend, where the ‘lapponica’s are continuously decreasing.

15,000 30,000 10,000 12,000 25,000 8,000 20,000 9,000 6,000 15,000 6,000 4,000 10,000 3,000 5,000 2,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

10,000 60,000 8,000 50,000 40,000 6,000 30,000 4,000 20,000 2,000 10,000 0 0 2020 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Bar-tailed Godwit (lapponica) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea   (C) Denmark  

(D) Schleswig-Holstein   (E) Niedersachsen/Hamburg  (F) The Netherlands   strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

56 5 Subspecies accounts

5.7 Common Redshank (totanus)

05461 Tringa totanus totanus DK: Rødben D: Rotschenkel NL: Tureluur Figure 5.7.1-5.7.6 Trends of subspecies Com- 15,000 6,000 20,000 5,000 mon Redshank (totanus) in 12,000 16,000 the international Wad - 4,000 den Sea (WS) and the 9,000 12,000 3,000 four regions 1987/1988- 2016/2017; dots represent 6,000 2,000 8,000 annual averages; trendline 3,000 1,000 4,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits Trend DK Trend SH Trend NS Trend NL (dotted line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Birds from the Fennoscandia and north-western Russian population T. t. totanus, which winter in western Africa, pass through the Wadden Sea in April/May and July/August mainly. The overall trend is slightly decreasing, but very much contrasting within the Wadden Sea regions. Numbers are stable in the Netherlands, decreasing in the German parts of the Wadden Sea, but increasing in the Danish Wad- den Sea.

1,500 10,000 1,200 8,000

900 6,000

600 4,000 300 2,000 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

5,000 10,000 1,500 4,000 8,000 1,200 3,000 6,000 2,000 4,000

1,000 2,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands Trends for Common Redshank (totanus) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea   (C) Denmark   (D) Schleswig-Holstein   (E) Niedersachsen/Hamburg   (F) The Netherlands   strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

5 Subspecies accounts 57

5.8 Common Redshank (robusta)

Tringa totanus robusta 05462 DK: Rødben D: Rotschenkel NL: Tureluur Figure 5.8.1-5.8.6 20,000 10,000 Trends of subspecies Com- 16,000 8,000 mon Redshank (robusta) in the international Wad- 6,000 12,000 den Sea (WS) and the 4,000 four regions 1987/1988- 8,000 2016/2017; dots represent 2,000 4,000 annual averages; trendline 0 calculated by Trendspotter 2020 0 1985 1990 1995 2000 2005 2010 2015 2020 (solid line) together with the 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL ± 95 % confidence limits (dotted line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Only birds of the subspecies T. t. robusta from islandic breeding grounds winter in the Wadden Sea region. Thus, numbers and trends reflect the occurrence of severe winters. Numbers increased up to the mid 1990’s, but dropped rapidly due to the severe winters in the mid 1990s, recovered until 2005/2006 and decreased since then again due to a series of cold winters during the last years. Almost the same pattern appears mainly in the German parts of the Wadden Sea. The winter-effect is not that clear in the Dutch Wadden Sea.

1,500 5,000 1,200 4,000

900 3,000

600 2,000 300 1,000 0 0 2020 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

5,000 10,000 4,000 8,000 3,000 6,000 2,000 4,000

1,000 2,000

0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Common Redshank (robusta) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea   (C) Denmark   (D) Schleswig-Holstein   (E) Niedersachsen/Hamburg  (F) The Netherlands 

strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

58 5 Subspecies accounts

5.9 Ruddy Turnstone (Greenland & NE Canada)

05611 Arenaria interpres morinella DK: Stenvender D: Steinwälzer NL: Steenloper Figure 5.9.1-5.9.6 5,000 Trends of subspecies Ruddy 10,000 Turnstone (Greenland & NE 4,000 8,000 Canada) in the international 3,000 Wadden Sea (WS) and the 6,000 four regions 1987/1988- 2,000 2016/2017; dots represent 4,000 annual averages; trendline 1,000 2,000 calculated by Trendspotter 0 (solid line) together with the 0 1985 1990 1995 2000 2005 2010 2015 2020 ± 95 % confidence limits 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL (dotted line). (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared

Explanatory Note Birds from the Greenlandic and north-eastern Canadian population stay in the Wadden Sea during winter, but also in western Europe and north-western Africa. Like in Tringa t. robusta wintering numbers are reflecting the occurrence of severe winters during the last 25 years. Numbers increased after the severe winters in the mid 1980s, dropped again due to the severe winters in the mid 1990s, recovered continuously for several years until 2008 and dropped again during the row of severe winters around 2009-2011. Opposite to the Tringa t. robusta this pattern mainly appears in the Dutch Wadden Sea, where the biggest numbers are found.

500 1,500 2,000 400 1,200 1,600

300 900 1,200

200 600 800 100 300 400 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

2,000 5,000 1,600 4,000 1,200 3,000 800 2,000

400 1,000

0 0 2020 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Ruddy Turnstone (Greenland & NE Canada) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea  (C) Denmark  

(D) Schleswig-Holstein  (E) Niedersachsen/Hamburg   (F) The Netherlands  

strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

5 Subspecies accounts 59

5.10 Ruddy Turnstone (Scandinavia-Western Russia)

Arenaria interpres 05612 DK: Stenvender D: Steinwälzer NL: Steenloper Figure 5.10.1-5.10.6 1,500 1,000 10,000 Trends of subspecies Ruddy 1,200 800 Turnstone (Scandinavia 8,000 - Western Russia) in the 600 900 6,000 international Wadden Sea 400 (WS) and the four regions 4,000 600 1987/1988-2016/2017; dots 200 300 2,000 represent annual aver- 0 ages; trendline calculated 0 1985 1990 1995 2000 2005 2010 2015 2020 by Trendspotter (solid line) 1985 1990 1995 2000 2005 2010 2015 2020 Trend DK Trend SH Trend NS Trend NL together with the ± 95 % confidence limits (dotted (A) Overall trend in the international Wadden Sea (B) Trends in the different countries compared line).

Explanatory Note Birds from the Scandinavian and north-western Russian population winter in western Africa and pass the Wadden Sea mainly in May and July. The overall trend is stable. There are small differences within the regions with a stable to slight decreasing numbers in the Netherlands, a slight long-term decrease in Schleswig-Holstein too, a more positive trend in Niedersachsen and the small numbers in Denmark dropped.

150 500 120 400

90 300

60 200 30 100 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

15,000 500 1,000 400 800 12,000 300 600 9,000 200 400 6,000

100 200 3,000 0 0 0 1985 1990 1995 2000 2005 2010 2015 2020 1985 1990 1995 2000 2005 2010 2015 2020

(E) Niedersachsen/Hamburg (F) The Netherlands

Trends for Ruddy Turnstone (Scandinavia - Western Russia) in the Wadden Sea Figures represent the trend 1987/1988 to 2016/2017, taking into account data from those months in which this subspecies dominates counts in the Wadden Sea. Numbers on the y-axis represent monthly mean occurrences. Dots are the individual yearly estimates, solid lines the trend calculated by TrendSpotter, dotted lines the 95% confidence limits of the trend lines. Area Period 1987/88 - 2007/08 - 2016/17 2016/17 (A)/(B) International Wadden Sea   (C) Denmark   (D) Schleswig-Holstein   (E) Niedersachsen/Hamburg  (F) The Netherlands   strong increase strong decrease moderate increase moderate decrease stable uncertain

Migratory bird trends until 2016/2017

6 References

Bell, M. C. (1995): UINDEX4. A computer pro- JMMB 2008. Trends of Migratory and wintering gramme for estimating population index num- waterbirds in the Wadden Sea 1987/88 – 2006/07. bers by the Underhill method. The Wildfowl & www.waddensea-secretariat.org. Wilhelmshav- Wetlands Trust, Slimbridge, UK. 9 p. en, Germany.

Blew, J., Günther, K., Hälterlein, B., Kleefstra, R., JMMB 2009. Trends of Migratory and win- Laursen,K., Scheiffarth, G. (2015). Trends of Mi- tering waterbirds in the Wadden Sea 1987/88 – 2007/08. www.waddensea-secretariat.org. gratory and Wintering Waterbirds in the Wadden Sea 1987/1988 - 2011/2012. Wadden Sea Eco- Wilhelmshaven, Germany. system No. 34. Common Wadden Sea Secretariat, JMMB 2010. Trends of Migratory and win- Joint Monitoring Group of Migratory Birds in the tering waterbirds in the Wadden Sea Wadden Sea, Wilhelmshaven, Germany. 1987/88 – 2008/09.www.waddensea-secretariat.org. Blew, J., Günther, K., Hälterlein, B., Kleefstra, R., Wilhelmshaven, Germany. Laursen,K., Scheiffarth, G. 2016. Trends of Migra- JMMB 2011. Trends of Migratory and win- tory and Wintering Waterbirds in the Wadden tering waterbirds in the Wadden Sea Sea 1987/1988 - 2013/2014. Wadden Sea Eco- 1987/88 – 2009/10.www.waddensea-secretariat.org. system No. 37. Common Wadden Sea Secretariat, Wilhelmshaven, Germany. Joint Monitoring Group of Migratory Birds in the Wadden Sea, Wilhelmshaven, Germany. JMMB 2013. Blew, J., Günther, K., Hälterlein, B., Kleefstra, R., Laursen,K., Scheiffarth, G. 2013. Blew, J., Günther, K., Laursen, K., van Roomen, M., Trends of Migratory and Wintering Waterbirds Südbeck, P., Eskildsen, K., and Potel, P., (2007): in the Wadden Sea 1987/1988 - 2010/2011. Trends of waterbird populations in the interna- Wadden Sea Ecosystem No. 31. tional Wadden Sea 1987-2004 - an update. P. 9-31 in Reineking & Südbeck, 2007. Seriously Kleefstra, R. & Kempf, N. 2013. Moulting Shel- Declining Trends in Migratory Waterbirds: Caus- ducks in the Wadden Sea 2010-2012. Common es-Concerns-Consequences. Proceedings of the Wadden Sea Secretariat, Joint Monitoring Group International Workshop on 31 August 2006 in of Migratory Birds in the Wadden Sea, Wilhelms- Wilhelmshaven, Germany. Wadden Sea Ecosys- haven, Germany. tem No. 23. Laursen, K., Blew, J., Eskildsen, K., Günther, K., Blew, J. & Südbeck, P. (2005): Migratory Water- Hälterlein, B., Kleefstra, R., Lüerßen, G., Potel, P., birds in the Wadden Sea 1980-2000. Wadden Schrader, S. 2010. Migratory Waterbirds in the Sea Ecosystem No. 20. Common Wadden Sea Wadden Sea 1987 2008. Wadden Sea Ecosys- Secretariat, Trilateral Monitoring and Assess- tem No.30. Common Wadden Sea Secretariat, ment Group, Joint Monitoring Group of Migra- Joint Monitoring Group of Migratory Birds in the tory Birds in the Wadden Sea, Wilhelmshaven, Wadden Sea, Wilhelmshaven, Germany. Germany. Meltofte, H., J. Blew, J. Frikke, H.-U. Rösner, C. J. Essink, K., C. Dettmann, H. Farke, K. Laursen, G. Smit (1994): Numbers and distribution of water- Lüerßen, H. Marencic, W. Wiersinga (Eds.) (2005): birds in the Wadden Sea. Results and evaluation Wadden Sea Quality Status Report 2004. Wad- of 36 simultaneous counts in the Dutch-German- den Sea Ecosystems No. 19, Trilateral Monitor- Danish Wadden Sea 1980-1991. IWRB Publ. 34 / ing and Assessment Group, CommonWadden Sea Wader Study Group Bull. 49, Special Issue 192 p. Secretariat, Wilhelmshaven, Germany. 360 p. Poot, M., L. M. Rasmussen, M. van Roomen, H.-U. Fox, A.D., Dalby, l., Christensen, T.K., Nagy, S., Rösner, P. Südbeck (1996): Migratory Waterbirds Balsby, T.J.S., Crowe, O., Clausen, P., Deeuninck, in the Wadden Sea 1993/94. Wadden Sea Eco- system No. 5. Common Wadden Sea Secretariat B., Devos, K., Holt, C.A., Hornmann, M., Keller, V., Langendoen, T., Lehikoinen, A., Lorentsen, S.H., and Trilateral Monitoring and Assessment Group, Molina, B., Nilsson, l., Stipniece, A., Svenning, J.C. Wilhelmshaven, Germany. 79 p. & Wahl, J. 2015. Seeking explanations for recent Reneerkens, J., Loonstra, J., Spaans, B. & Piersma, changes in abundance of wintering Eurasian T. 2012. Grote aantallen Drieteenstrandlopers uit Wigeon (Anas penelope) in northwest Europe. allerlei windstreken bij Griend, nazomer 2011. Li- Ornis Fennica 93: 12–25. mosa 85: 73 - 79. JMMB 2007. Trends of Migratory and winter- Rösner, H.-U., M. v. Roomen, P. Südbeck, L. M. ing waterbirds in the Wadden Sea 1987/88 – Rasmussen (1994): Migratory Waterbirds in the 2005/06. www.waddensea-secretariat.org. Wil- Wadden Sea 1992/93. Wadden Sea Ecosystem helmshaven, Germany. No. 2. Common Wadden Sea Secretariat and Tri-

Migratory bird trends until 2016/2017

lateral Monitoring and Assessment Group, Wil- helmshaven, Germany. 72 p. Rösner, H.-U. (1993): The joint monitoring project for migratory birds in the Wadden Sea. Com- mon Wadden Sea Secretariat, Wilhelmshaven, Germany. 16 p. Soldaat, L., H. Visser, M. van Roomen, A. van Strien (2007): Smoothing and trend detection in waterbird monitoring data using structual time- series analysis and the Kalman filter. Journal of Ornithology, 148: 351-357.

Underhill, L. G., R. P. Prýs-Jones (1994): Index numbers for waterbird populations. I. Review and methodology. Journal of Applied Ecology, 31: 463-480. Visser, H. (2004): Estimation and detection of flexible trends. Atmospheric Environment, 38: 4135-4145.

Wetlands International (2013). “Waterbird Popula- tion Estimates” . Retrieved from wpe.wetlands.org

Migratory bird trends until 2016/2017

Annex 1 Assignment of species according to living conditions

Table A1.1 Assignment of species Food Feeding habitats according to food and feeding habitats

coastal shellfish worms fish other vertebratesplants omnivoroussalt marsh tidal dunes beach & offshoregrassland Great Cormorant x x Eurasian Spoonbill x x Barnacle Goose x x Brent Goose x x Common Shelduck x x Eurasian Wigeon x x Common Teal x x Mallard x x Northern Pintail x x Northern Shoveler x x Common Eider x x Eurasian Oystercatcher x x Pied Avocet x x Great Ringed Plover x x Kentish Plover x x European Golden Plover x x Grey Plover x x Northern Lapwing x x Red Knot x x Sanderling x x Curlew Sandpiper x x Dunlin x x Ruff x x Bar-tailed Godwit x x Whimbrel x x Eurasian Curlew x x Spotted Redshank x x Common Redshank x x Common Greenshank x x Ruddy Turnstone x x Black-headed Gull x x Common Gull x x European Herring Gull x x Great Black-backed Gull x x Total number of species 4 11 4 8 6 1 7 21 0 3 3

Photo: John Frikke

Migratory bird trends until 2016/2017

Table A1.2 Breeding range Wintering range Assignment of species according to breeding and wintering range.

arctic breeder non-arctic breeder Europe Africa Great Cormorant x x Eurasian Spoonbill x x Barnacle Goose x x Brent Goose x x Common Shelduck x x Eurasian Wigeon x x Common Teal x x Mallard x x Northern Pintail x x Northern Shoveler x x Common Eider x x Eurasian Oystercatcher x x Pied Avocet x x Great Ringed Plover x x Kentish Plover x x European Golden Plover x x Grey Plover x x Northern Lapwing x x Red Knot x x Sanderling x x Curlew Sandpiper x x Dunlin x x Ruff x x Bar-tailed Godwit x x Whimbrel x x Eurasian Curlew x x Spotted Redshank x x Common Redshank x x Common Greenshank x x Ruddy Turnstone x x Black-headed Gull x x Common Gull x x European Herring Gull x x Great Black-backed Gull x x Total number of species 13 21 22 12

Photo: Klaus Günther

Migratory bird trends until 2016/2017

Annex 2 Counting units in the Wadden Sea

Figure A2.1 The international Wadden Sea, including delimitations of all counting units and spring tide counting sites Counting units and spring tide counting sites (STC-sites) in the international Wadden Sea

Migratory bird trends until 2016/2017

Annex 3 Species List

List of the species monitored in the Trilateral Monitoring and Assessment Program (TMAP) Euring English name Scientific name Dansk navn Deutscger Name Nederlandse naam 00720 Great Cormorant Phalacrocorax carbo Skarv Kormoran Aalscholver 01440 Eurasian Spoonbill Platalea leucorodia Skestork Löffler Lepelaar

01670 Barnacle Goose Branta leucopsis Bramgås Nonnengans Brandgans 01680 Dark-bellied Brent Goose Branta bernicla Knortegås Ringelgans Rotgans 01610 Greylag Goose* Anser anser Grågås Graugans Grauwe Gans 01730 Common shelduck Tadorna tadorna Gravand Brandgans Bergeend 01790 Eurasian Wigeon Anas penelope Pibeand Pfeifente Smient 01840 Common Teal Anas crecca Krikand Krickente Wintertaling 01860 Mallard Anas platyrhynchos Gråand Stockente Wilde Eend 01890 Northern Pintail Anas acuta Spidsand Spießente Pijlstaart 01940 Northern Shoveler Anas clypeata Skeand Löffelente Slobeend

02060 Common Eider Somateria mollissima Ederfugl Eiderente Eidereend 02430 White-Tailed Eagle* Haliaeetus albicilla Havørn Seeadler Zeearend 02900 Rough-Legged Buzzard* Buteo lagopus Fjeldvåge Rauhfußbussard Ruigpootbuizerd 03090 Merlin* Falco columbarius Dværgfalk Merlin Smelleken

03200 Peregrine Falcon* Falco peregrinus Vandrefalk Wanderfalke Slechtvalk 04500 Eurasian Oystercatcher Haematopus ostralegus Strandskade Austernfischer Scholekster 04560 Pied Avocet Recurvirostra avosetta Klyde Säbelschnäbler Kluut 04700 Great Ringed Plover Charadrius hiaticula Stor Præstekrave Sandregenpfeifer Bontbekplevier

04770 Kentish Plover Charadrius alexandrinus Hvidbrystet Præstekrave Seeregenpfeifer Strandplevier 04850 Golden Plover Pluvialis apricaria Hjejle; Hedehjejle Goldregenpfeifer Goudplevie 04860 Grey Plover Pluvialis squatarola Strandhjejle Kiebitzregenpfeifer Zilverplevier 04930 Northern Lapwing Vanellus vanellus Vibe Kiebitz Kievit 04960 Red Knot Calidris canutus Islandsk Ryle Knutt Kanoetstrandloper 04970 Sanderling Calidris alba Sandløber Sanderling Drieteenstrandloper 05090 Curlew Sandpiper Calidris ferruginea Krumnæbbet Ryle Sichelstrandläufer Krombekstrandloper 05120 Dunlin Calidris alpina Almindelig Ryle Alpenstrandläufer Bonte Strandloper 05170 Ruff Philomachus pugnax Brushane Kampfläufer Kemphaan

05320 Black-tailed Godwit* Limosa limosa Stor Kobbersneppe Uferschnepfe Grutto 05340 Bar-Tailed Godwit Limosa lapponica Lille Kobbersneppe Pfuhlschnepfe Rosse Grutto 05380 Whimbrel Numenius phaeopus Lille Regnspove Regenbrachvogel Regenwulp 05410 Eurasian Curlew Numenius arquata Stor Regnspove Großer Brachvogel Wulp

05450 Spotted Redshank Tringa erythropus Sortklire Dunkler Wasserläufer Zwarte Ruiter 05460 Common Redshank Tringa totanus Rødben Rotschenkel Tureluur 05480 Common Greenshank Tringa nebularia Hvidklire Grünschenkel Groenpootruiter 05610 Ruddy Turnstone Arenaria interpres Stenvender Steinwälzer Steenloper

05820 Common Black-headed Gull Larus ridibundus Hættemåge Lachmöwe Kokmeeuw 05900 Common Gull Larus canus Stormmåge Sturmmöwe Stormmeeuw 05910 Lesser Black-backed Gull* Larus fuscus Sildemåge Heringsmöwe Kleine Mantelmeeuw 05920 Herring Gull Larus argentatus Sølvmåge Silbermöwe Zilvermeeuw 06000 Great Black-backed Gull Larus marinus Svartbag Mantelmöwe Grote Mantelmeeuw 09780 Shore (Horned) Lark* Eremophila alpestris Bjerglærke Ohrenlerche Strandleeuwerik 16620 Twite* Carduelis flavirostris Bjergirisk Berghänfling Frater 18500 Snow Bunting* Plectrophenax nivalis Snespurv Schneeammer Sneeuwgors * Species where data does not allow trend analysis

Migratory bird trends until 2016/2017

Issues of the Publication Series „Wadden Sea Ecosystem“

No. 1: Breeding Birds in the Wadden Sea 1991. 1994. No. 2: Migratory Waterbirds in the Wadden Sea1992/93. 1994. No. 3: Guidelines for Monitoring of Breeding Birds in the Wadden Sea (in Dutch, German, Danish). 1995. No. 4: Breeding Birds on Census Arteas 1990 until 1994. Status of Shorelark, Twite and Snow Bunting in the Wadden Sea. 1997. No. 5: Migratory Waterbirds in the Wadden Sea 1993/94. 1996. No. 6: Trilateral Monitoring and Assessment Program. TMAP Expert Workshops 1995/96. 1996. No. 7: Assessment of the Wadden Sea Ecosystem. 1997. No. 8: Monitoring Breeding Success of Coastal Birds. Monitoring Pollutants in Coastal Bird Eggs in the Wadden Sea. 1998. No. 9: Wadden Sea Quality Status Report 1999. 1999. No. 10: Breeding Birds in the Wadden Sea in 1996. 2000. No. 11: Contaminants in Bird Eggs in the Wadden Sea. Spatial and Temporal Trends 1999  2000. 2001. No. 12: Lancewad. Landscape and Cultural Heritage in the Wadden Sea Region. 2001. No. 13: Final Report of the Trilateral Working Group on Coastal Protection and Sea Level Rise. 2001. No. 14: Wadden Sea Specific Eutrophication Criteria. 2001. No. 15: Common and Grey Seals in the Wadden Sea. TSEGplus Report March/June 2001.2002. No. 16: High Tide Roosts in the Wadden Sea. A Review of Bird Distribution, Protection Regimes and Potential Sources of Anthropogenic Discturbance. 2003. No. 17: Management of North Sea Harbour and Grey Seal Populations. Proceedings of the International Symposium at EcoMare, Texel, The Netherlands November 29  30, 2002. 2003. No. 18: Contaminants in Bird Eggs in the Wadden Sea. Recent Spatial and Temporal Trends. Seabirds at Risk? Effects of Environmental Chemicals on Reproductive Success and Mass Growth of Seabirds at the Wadden Sea in the Mid 1990s. 2004. No. 19: Wadden Sea Quality Status Report 2004. 2005. No. 20: Migratory Waterbirds in the Wadden Sea 1980 - 2000. 2005. No. 21: Coastal Protection and Sea Level Rise - Solutions for Sustainable Coastal Protection. 2005 No. 22: Breeding Birds in the Wadden Sea in 2001. 2006. No. 23: Seriously Declining Trends in Migratory Waterbirds: Causes-Concerns-Consequences. Proceedings of the International Workshop on 31 August 2005 in Wilhelmshaven, Germany. 2007. No. 24: Nomination of the Dutch-German Wadden Sea as World Heritage Site. 2008. No. 25: Wadden Sea Quality Status Report 2009. 2009. No. 26: Science for Nature Conservation and Managment: The Wadden Sea Ecosystem and EU Direc- tives. Proceedings of the 12th International Scientific Wadden Sea Symposium in Wilhelmshaven, Germany, 30 March - 3 April 2009. 2010. No. 27: Exploring contrasting trends of migratory waterbirds in the international Wadden Sea. 2010. No. 28: CPSL Third Report. The role of spatial planning and sediment in coastal risk management. 2010. No. 29: The Wadden Sea - A Universally Outstanding Tidal Wetland. The Wadden Sea Quality Status Report. Synthesis Report 2010. No. 30: Migratory Waterbirds in the Wadden Sea 1987-2008. 2010. No. 31: Trends of Migratory and Wintering Waterbirds in the Wadden Sea 1987/1988-2016/2017. 2013. No. 32: TMAP-Typology of Coastal Vegetation in the Wadden Sea Area. 2014. No. 33: Dynamic Islands in the Wadden Sea. 2014. No. 34: Trends of Migratory and Wintering Waterbirds in the Wadden Sea 1987/1988-2011/2012. 2015. No. 35: Trends of Breeding Birds in the Wadden Sea 1991 - 2013. 2015. No. 36: Breeding success in the Wadden Sea 2009-2012. 2016. No. 37: Trends of Migratory and Wintering Waterbirds in the Wadden Sea 1987/1988-2013/2014. 2016. No. 38: Managing predation risk for breeding birds in the Wadden Sea. 2019 No. 39: Trends of Migratory and Wintering Waterbirds in the Wadden Sea 1987/1988-2016/2017. 2019.

Migratory bird trends until 2016/2017

68 The Trilateral Monitoring and

Assessment Program (TMAP)

COMMON WADDEN SEA SECRETARIAT Virchowstrasse 1 D-26382 Wilhelmshaven Federal Republic of Germany www.waddensea-secretariat.org

Migratory bird trends until 2016/2017 ISSN 0946-896X