Populations d’oiseaux d’eau hivernants sur le littoral sur la période 2007-2012

• France occupies a central position on the East-Atlantic migration axis between Siberia, northern Europe, eastern Europe, and West Africa. It hosts the 3rd largest wintering waterbird population in Europe, after the Netherlands and the United Kingdom. On average each year, 1.5 million waterbirds are counted in January within the coastal perimeters monitored under the "Wetlands International" programme (international NGO based in the Netherlands). This represents more than half (56%) of all waterbirds counted across the entire metropolitan territory. The coast and its numerous wetlands—marshes, mudflats, salt meadows, lagoons, and ponds—therefore play a major role in waterbird wintering. • The largest groups of waterbirds wintering on the coast are waders, dabbling ducks and coots, and gulls. • For gulls, counts conducted under the Wetlands programme are incomplete. A dedicated survey of this group conducted in winter 2011–2012 indicates populations close to 818,500 individuals, which would make it the largest group of wintering birds in this territory.

• More than 630,000 waders are counted on average each year on the coast, representing nearly 78% of the French population. Some species are exclusively found on the coast, such as the Black-tailed Godwit, Grey Plover, or Sanderling. This proportion is 49% for dabbling ducks and coots, 47% for divers and grebes, and 35% for herons. For cormorants, which prefer freshwater lakes and lowland rivers, this figure is only 32%, and just 19% for rails. • Wintering waterbirds counted by group, average 2007–2012 — Note: for gulls, Wetlands programme counts are incomplete and do not fully reflect wintering populations on the coast.

• The highest concentrations of birds are found on the Atlantic coast and the Bouches-du-Rhône littoral. Specifically, the main metropolitan coastal wintering sites are the Camargue, the Baie de l'Aiguillon national nature reserve and Pointe d'Arçay, the Arcachon Basin, the Bay of Mont Saint-Michel, and the Moëze national nature reserve, between the Île d'Oléron and the mainland. • Distribution of birds varies by group. Waders are mainly found in the large bays and gulfs of the Atlantic coast. Herons are most numerous on the Mediterranean coast; pink flamingos represent the vast majority of wintering herons on the metropolitan coast. • Among monitored species, metropolitan coasts harbor more than 10% of the biogeographic populations of Brent Goose, Avocet, Dunlin, Sanderling, Kentish Plover, Turnstone, Shelduck, Grey Plover, and Curlew Sandpiper (in decreasing order of proportion on the metropolitan coast).

• Compared to the 2000–2005 period, most wintering waterbird populations on the coast are increasing, except on the Mediterranean coast. • Average number of wintering waterbirds by group and coastline, 2007–2012 average — Note: figures have been rounded. For gulls, Wetlands programme counts are incomplete and do not fully reflect wintering populations on the coast.

Waterbirds are not evenly distributed along our coasts. Climate, the extent and diversity of wetlands, the presence of undisturbed areas, and the level of shoreline development all impact their distribution.

• The highest concentrations are found in Bouches-du-Rhône and along the Atlantic coast, from Vendée to Gironde. Breton, English Channel, and Picardy departments have overall populations roughly half as large. Populations are significantly lower on other coastal stretches, particularly in Languedoc-Roussillon where wintering bird populations appear to have recently declined, mainly due to a drop in rail and gull numbers (closure of several open-air landfills caused population decline, particularly of the Yellow-legged Gull). Waterbird groups are also distributed differently across maritime coastlines. Waders, mainly dependent on intertidal mudflats where they feed, concentrate on the English Channel–North Sea and Atlantic arc. Lacking true intertidal space, the Mediterranean coast, with its many water bodies and lagoons, is more suitable for dabbling ducks and herons. • Distribution by departmental coastal stretch of wintering waterbirds, 2007–2012 average

Trends in numbers compared to the 2000–2005 average appear positive on the Atlantic coast and English Channel–North Sea, notably due to improved counting coverage. The negative trend on the Mediterranean coast is mainly due to gull decline. Overall, across the entire coast, wintering waterbird numbers appear to have slightly increased.

• Among the top ten metropolitan coastal wintering sites (average annual numbers 2007–2012): • Camargue, 181,000 birds; • Baie de l'Aiguillon and Pointe d'Arçay, 102,000 birds; • Arcachon Basin, 101,000 birds; • Bay of Mont-Saint-Michel, 88,000 birds; • Moëze Nature Reserve (Charente-Seudre), 85,000 birds; • Lac de Grand-Lieu: 70,600; • Guérandaise Peninsula, 60,000 birds; • Rhine Valley (departments 67 and 68): 58,000 birds; • Gulf of Morbihan, 58,000 birds; • Picardy coast, 50,000 birds.

• Dabbling ducks and coots are present along most of our coasts. The largest populations are found in the Camargue (over 170,000 individuals) and on the Atlantic coast, from Vendée to Gironde (between 60,000 and 70,000 individuals per department). They are found on sheltered coasts such as large bays and in marsh and pond regions. • Distribution of dabbling ducks and coots, 2007–2012 • Five main wintering sites are involved: • The Camargue is formed by a mosaic of ponds, salt ponds, mudflats, and reed beds that enable the wintering of many ducks, such as Mallard, Wigeon, Northern Shoveler, Gadwall, Red-crested Pochard, and Bewick's Swan. They benefit from vast preserved and undisturbed spaces; • The Arcachon Basin, with its eelgrass beds, plays an essential role in wintering Brent Geese, with France hosting a very significant proportion of the Siberian population (nearly 50% depending on the year); • Baie de l'Aiguillon and Pointe d'Arçay host a significant proportion of wintering Northern Pintail, Greylag Goose, and Shelduck populations; • The Moëze nature reserve welcomes many ducks such as the Teal and significant numbers of Brent Geese, Greylag Geese, and Shelducks; • The Gulf of Morbihan harbors an important population of Goldeneye and Red-breasted Merganser.

• Generally gregarious and sociable, waders are mainly found on the Atlantic and English Channel–North Sea coasts. Feeding primarily on the shore and in mudflat zones, main populations are located in sheltered, shallow areas such as bays and gulfs. • Distribution of waders, 2007–2012 • The six main wintering sites are: • The Baie de l'Aiguillon national nature reserve and Pointe d'Arçay (60,000 waders on average): it hosts a significant Avocet population, as well as Black-tailed Godwit, Curlew Sandpiper, and Dunlin. • The Moëze national nature reserve: this protected territory winters an average of 58,000 waders. There are significant congregations of Dunlin and Curlew Sandpiper, as well as Golden Plover and Grey Plover. • The Bay of Mont Saint-Michel: with 46,000 wintering waders on average during 2007–2012, this is an important wintering site for species such as Dunlin, Whimbrel, Eurasian Oystercatcher, and Grey Plover. • The Arcachon Basin (40,000 waders): Dunlin represents the bulk of the wader contingent in the basin. This is followed by species such as Whimbrel and Grey Plover. • Bourgneuf Bay and Noirmoutier (33,000 waders) is an important site for wintering Avocet, Black-tailed Godwit, Curlew Sandpiper, and Dunlin. • The Guérandaise Peninsula including Traicts du Croisic and salt marshes (33,000 waders).

• The Mediterranean coast, with its many lagoons and coastal ponds, hosts a large number of wintering herons, including a very significant number of Pink Flamingos. They represent the bulk of herons present on the coast in winter. On certain sites such as Leucate Lagoon, Aigues-Mortes salt ponds, or the Camargue, they constitute almost all herons present. Two important sites are located on the Atlantic coast: • The Arcachon Basin, which winters significant numbers of Little Egret, Night Heron, White Stork, and Spoonbill; • The Guérandaise Peninsula, which winters large populations of Little Egret and Spoonbill. Heron populations are quite weak on the English Channel–North Sea coasts, where natural habitats are less suitable. The two major sites are inland: Arjuzanx in the Landes, and Lake Der in Champagne-Ardenne, harboring significant Common Crane populations. • Distribution of herons, 2007–2012

• The ecological requirements of gulls are generally less stringent than those of the previous species groups. They are found along large water bodies, in ports, salt marshes, urban parks, or near landfills. The main wintering sites are the Bay of Mont-Saint-Michel, Lake Grandlieu, the Pas-de-Calais coast, the Picardy coast, the Normandy coast, and the Seine estuary. • Thus, the French coast plays a major role in the wintering of many dabbling duck species but especially waders, for which access to soft shore and undisturbed roost areas at high tide are essential. According to biogeographic population estimates provided by Wetlands International (2012), metropolitan coasts host more than 10% of populations of the following species (in decreasing order of importance): Brent Goose, Avocet, Dunlin, Sanderling, Kentish Plover, Turnstone, Shelduck, Grey Plover, and Curlew Sandpiper.

Population changes vary by species and species group, but an overall positive trend has been observed since the 1980s. In France, many conservation and management measures since the 1980s have contributed to improving habitat quality for waterbirds, such as the creation of nature reserves at major coastal wintering sites. Greater tranquility at wintering sites and better access to food resources have benefited the vast majority of populations whose conservation status was highly unfavorable.

Among dabbling ducks and coots, ten species are significantly increasing (such as Red-breasted Merganser, Greylag Goose, and Brent Goose), seven are declining (such as Tufted Duck and Pochard), four are stable (including Common Scoter and Bewick's Swan), and nine are considered to have no clearly defined trend (such as Whooper Swan or Anser anser).

• For waders, all wintering populations have increased since the 1980s, except for Ruff, which remains stable. They benefit from low disturbance and protection of large coastal wetlands, with more than two-thirds of recorded populations in protected areas (Grey Plover, Dunlin, Black-tailed Godwit, and Common Redshank). This increase is all the more significant because, for some species, France hosts a substantial proportion of biogeographic populations. • Evolution of wintering waterbird populations in France, 1980–2012

• Wintering waterbird surveys have been conducted annually for over forty years. Counts are conducted in mid-January, at the height of winter when wintering populations have the least movement (excluding cold waves). These nationally coordinated counts, conducted by the Ligue pour la Protection des Oiseaux (LPO), are part of an international monitoring programme under the auspices of Wetlands International. • In France, approximately 1,500 sites shown on the map below are monitored. These are grouped into nearly 400 functional sites, coherent assemblages such as a river section, marsh, pond group, or lagoon network. • For this study focusing exclusively on the coast, a selection was made from these functional sites. Only 90 of them located within 10 kilometers of the coast were taken into account.

• Dabbling ducks and coots: geese, ducks, swans, geese…; • Waders: shanks, godwits, sandpipers, curlews, plovers…; • Gulls: gulls, terns, gulls, and terns; • Herons: egrets, storks, pink flamingo, common crane, and herons; • Divers and grebes: Great Crested Grebe, Little Grebe, Arctic Diver, Black-throated Diver…; • Cormorants: Great Cormorant and Shag; • Rails: Common Moorhen, crakes, and Water Rail.

Participating associations and organizations in the surveys are as follows (2013): A.A. Marais du Vigueirat; A.A. Réserve de Séné; ADENA Bagnas; A.L.E.P.E.; Association de Rosquerno; Association Hirondelle; A.N.V.L.; A.O.M. Saône-et-Loire.; A.R.O. Midi-Pyrénées.; Ass. Naturaliste Ariégeoise; Aude Nature; Bretagne Vivante Concarneau-Trégunc; Bretagne Vivante Douarnenez; Bretagne Vivante Ille et Vilaine; Bretagne Vivante Pays de Vannes; Bretagne Vivante Quimper-Pont l'Abbé; Bretagne Vivante réseau des Réserves; C.C. Pays d'Iroise; C.E.N. Corse; C.E.E. de Provence; C.G. Gironde; C.G. Haute-Corse; C.G. Morbihan; C.O.R.A. Ain; C.O.R. Île-de-France; C.R.E.N. Poitou-Charentes; Centre Ornithologique Lorrain; CHARENTE NATURE; Club Ornithologique gersois; Comité local 65; CREN Languedoc-Roussillon; Conservatoire du Littoral; Eure-et-Loir Nature; F.D.C. 09; F.D.C. 13; F.D.C. 33; F.D.C. 56; F.D.C. 85; G.E.O. Côtes d'Armor; G.O. Breton (Finistère); G.O. Breton (Morbihan); G.O. des Deux-Sèvres; G.O. Du Roussillon; G.O. et Naturaliste du Nord-Pas-de-Calais; G.O. Normand; Groupe Sarthois Ornithologique; Indre Nature; LE RENARD; Les Naturalistes de l'Hérault; Loiret Nature Environnement; LPO Alsace; LPO Anjou; LPO Aquitaine; LPO Ardèche; LPO Aude; LPO Audomarois; LPO Auvergne; LPO Brenne; LPO Champagne-Ardenne; LPO Charente-Maritime; LPO Cher; LPO Côte-d'Or; LPO Drôme; LPO Franche-Comté; LPO Haute-Normandie; LPO Haute-Savoie; LPO Hérault; LPO Ille-et-Vilaine; LPO Isère; LPO Loire; LPO Loire-Atlantique; LPO Marais Breton; LPO PACA; LPO Réseau Réserves; LPO Rhône; LPO Savoie; LPO Tarn; LPO Touraine; LPO Vendée; LPO Vienne; LPO Yonne; LPO BirdLife France; Maison de l'Estuaire; Mayenne Nature Environnement; Muséum Toulon; Natur-Essonne; Naturalistes 34; Nature 18; Nature Midi-Pyrénées; ONCFS - CNERA Avifaune migratrice; ONCFS/SD 13; ONCFS/SD 22; ONCFS/SD 29; ONCFS/SD 33; ONCFS/SD 44; ONCFS/SD 56; ONCFS/RNCFS golfe du Morbihan; ONCFS/Station de Chanteloup; ONCFS/Réseau Oiseaux d'Eau/F.D.C.; OBIOS; Parc du Marquenterre; P.N.R. Boucles Seine Normande; P.N.R. Landes de Gascogne; P.N.R. Narbonnaise en Méditerranée; P.N. Marin d'Iroise; Picardie Nature; P.O. du Teich; R.N.N. du Banc d'Arguin; R.N.N. de la Baie de St Brieuc; R.N.N. de la Baie de l'Aiguillon 17; R.N.N. de la Baie de l'Aiguillon 85; R.N.N. de Baie de Somme; R.N.N. de Chérine; R.N.N. des Marais de Séné; R.N.N. de Beauguillot; R.N.N. de Bagnas; R.N.N. de Biguglia; R.N.N. de Bruges; R.N.N. des 7 Iles; R.N.N. de Müllembourg; R.N.N. des Ramières; R.N.N. du Cousseau; R.N.N. du Marais d'Orx; R.N.N. du Val d'Allier; R.N.N. de l'Estuaire de la Seine; R.N.N. de la Mer d'Iroise; R.N.N. de Lilleau des Niges; R.N.N. de Moëze; R.N.N. de St-Denis-du-Payré; R.N.N. des Marais d'Yves; Réseau ornitho 65; S.E.P.A.N.S.O.; S.E.P.O. Limousin; SIAGM/projet PNR Golfe du Morbihan; SYMEL; S.N.P.N./R.N. de Grandlieu; S.N.P.N./R.N. de Camargue; S.O.B.A./Nature Nièvre; Soc. Sci. Nat. Tarn-et-Garonne; Sologne Nature Environnement; Station Biologique de la Tour-du-Valat.

Authors: Data and Statistical Studies Service (SDES), Ligue pour la protection des Oiseaux (LPO).