Population des oiseaux d’eau hivernants sur le littoral sur la période 2013-2016

• With its privileged position on the East-Atlantic migration corridor, France hosts the 3rd largest wintering waterfowl population in Europe. The coastline, with approximately 1.4 million birds on average every winter between 2013 and 2016, represents, depending on species groups, 16% to 76% of wintering birds counted on metropolitan territory. • The most numerous wintering waterfowl groups on the coastline are waders, ducks and coots, and gulls. With 670,000 birds on average over the study period, the coastline concentrates 76% of wintering waders in metropolitan France.

• The strongest concentrations of birds are located in Central-Atlantic and along the Bouches-du-Rhône coast. Specifically, the main coastal wintering sites are Camargue, the Bay of Aiguillon and Pointe d'Arçay, Moëze Nature Reserve, the Bay of Mont-Saint-Michel, and the Arcachon Basin. • Depending on the species groups, bird distribution differs. Waders are mainly located in large bays and gulfs of the Atlantic coast. Ducks are more numerous on the Mediterranean coastline.

• Among the monitored species, metropolitan coasts shelter over 10% of the biogeographic populations of brent goose, avocet, curlew sandpiper, sanderling, ringed plover, turnstone, shelduck, grey plover, and knot (in decreasing order of metropolitan coastal share). • 13 of the 15 wader species monitored have seen their populations increase since 1980. The picture is more mixed for ducks. Ten species are increasing while seven are declining, such as tufted duck and pintail.

France has a central position on the East-Atlantic migration corridor between Siberia, Europe, and West Africa. It hosts the 3rd largest wintering waterfowl population in Europe after the Netherlands and the United Kingdom. Over the 2013-2016 period, an average of 1.4 million waterfowl were counted in January within the coastal perimeters monitored under the "Wetlands International" program (international NGO based in the Netherlands). This represents more than one in two wintering birds in metropolitan France (50.5%). It is close to the annual average between 2000 and 2005 and lower than the 2007-2012 period. The coastline and its numerous wetlands—marshes, mudflats, salt meadows, lagoons, and ponds—therefore play a major role in waterfowl wintering.

The most numerous waterfowl groups to winter on the coastline are waders, ducks and coots, and gulls. For gulls, counts conducted under the Wetlands program are incomplete. A dedicated inventory of this group conducted in winter 2011-2012 indicates numbers close to 818,500 individuals, which would make it the largest wintering bird group in this territory.

Over 670,000 waders are counted, on average, each year on the coastline over the 2013-2016 period, or three-quarters of the metropolitan population. Some waders are entirely dependent on the coastline, such as black-tailed godwit, grey plover, or sanderling. This proportion is 42% for ducks and coots, 37% for divers and grebes, 35% for gulls, 21% for herons, and 16% for rails, which particularly favor freshwater ponds and lowland rivers.

Waterfowl are not distributed homogeneously along French coasts. Climate, surface areas, and diversity of wetlands including tidal flats, the presence of undisturbed zones, and the level of coastal development impact their distribution.

• The highest concentrations are located in Bouches-du-Rhône and Central-Atlantic (Vendée and Charente-Maritime). Each of these departmental coastal regions hosts more than 150,000 birds on average each year. Numbers are also significant in Gironde and from Manche to Loire-Atlantique departments. • Populations are lower on other coastal regions. This is notably the case for Occitanie coasts, where wintering bird populations appear to have recently declined, mainly due to decreased populations of rails and gulls (the closure of several open-air landfills caused population decline, particularly of yellow-legged gull). Waterfowl populations are also low in departments with few wetlands: Seine-Maritime, Calvados, Pyrénées-Atlantique, Var, and Alpes-Maritimes.

Waders are mainly dependent on intertidal mudflats where they feed. They concentrate on the English Channel–North Sea and Atlantic arc. Lacking genuine intertidal space, the Mediterranean coast, with its numerous ponds and lagoons, is more suitable for wintering herons and ducks.

• Specifically, seven of the ten largest metropolitan waterfowl wintering sites are located on the coastline (annual average between 2013 and 2016): • Camargue, 126,100 birds (*); • Bay of Aiguillon and Pointe d'Arçay, 110,700 (**); • Moëze Nature Reserve, 83,500 (*); • Bay of Mont-Saint-Michel, 79,800 (*); • Grand-Lieu Lake, 71,100; • Der-Chantecoq Lake, 69,800; • Arcachon Basin, 60,700 (*); • Morbihan Gulf, 55,200 (*); • Lacs Orient, Amance and Temple-Auzon, 53,800; • Guérande Peninsula, including Croisic channels, 52,700 (*). • *Decrease in numbers between 2007-2012 and 2013-2016 **Increase in numbers between 2007-2012 and 2013-2016

• Ducks and coots are present on most metropolitan coasts. The largest populations are located in Camargue (110,000 individuals, or one-fifth of the coastal total), and in the Atlantic, from Morbihan to Gironde. They are found on sheltered coasts such as large bays and in marsh and pond regions. • The five main coastal wintering sites are: • Camargue: with its mosaic of ponds, salt marshes, mudflats, and reed beds, this vast wetland enables wintering of numerous ducks. Main populations include mallard, teal, gadwall, pintail, and shoveler. Camargue also hosts a significant share of Bewick's swans, pochards, red-crested pochards, and greylag geese wintering on the coastline; • Bay of Aiguillon and Pointe d'Arçay shelter large populations of shelducks, mallards, brent geese, teals, and pintails. Approximately 30% of greylag geese and pintails wintering on metropolitan coasts are counted here; • Moëze nature reserve: main ducks wintering here are brent goose, mallard, shelduck, teal, and shoveler. Over 10% of shovelers and brent geese wintering on the metropolitan coastline are counted here; • Morbihan Gulf hosts significant populations of brent geese, shelducks, coots, mallards, and teals. It contains 65% of goldeneyes wintering on the coastline (less than 50) and 39% of red-breasted mergansers, nearly 1,000.

• Generally gregarious and social, waders are mainly located on Atlantic and English Channel coasts. Feeding mainly on tidal flats and mudflat zones, main populations are localized in sheltered and shallow areas such as bays, gulfs, and estuaries. • Main wintering sites are: • Bay of Aiguillon national nature reserve and Pointe d'Arçay (71,400 waders on average): main waders here are curlew sandpiper, avocet, black-tailed godwit, knot, and grey plover. The reserve shelters a significant share of avocet populations wintering on the coastline, as well as godwits and knots; • Bay of Mont-Saint-Michel: 58,500 waders winter there on average over the 2013-2016 period. It is an important wintering site for knot, whimbrel, oystercatcher, and grey plover; • Moëze national nature reserve: on this protected territory, 54,600 waders winter on average. Important numbers include curlew sandpipers, knots, black-tailed godwits, and golden plovers; • Arcachon Basin (39,200 waders): curlew sandpiper makes up the bulk of waders on the basin. Other species include turnstone, whimbrel, and grey plover.

• Heron populations are relatively low on English Channel and North Sea coasts, where natural habitats are unsuitable for their presence. They are more abundant in the Atlantic and Mediterranean. The two major sites are inland: Arjuzanx site in Landes, and Der Lake in Champagne-Ardennes, hosting large populations of common cranes. • Main coastal sites are: • Carcans-Hourtin pond and Cousseau nature reserve: hosting a fairly large population of common cranes, though in much smaller numbers than Arjuzanx and Der Lake sites; • Guérande Peninsula (including Croisic channels): this site harbors large colonies of little egrets, cattle egrets, grey herons, and spoonbills in notable expansion in recent years; • Camargue with mainly little egrets, glossy ibis, cranes, and grey herons. • Thus, the French coastline plays a major role in wintering numerous duck species but especially waders, for which access to soft substrates and undisturbed high-tide roost zones are essential. According to biogeographic population estimates provided by Wetlands International (2012), metropolitan coasts host over 10% of populations of the following species (in decreasing order of importance): brent goose, avocet, curlew sandpiper, sanderling, ringed plover, turnstone, shelduck, grey plover, and knot.

Population trends vary by species and species groups, but a general positive trend has been observed since the 1980s. In France, numerous conservation and management measures over the past forty years have helped increase habitat quality for waterfowl, such as the creation of nature reserves at main coastal wintering sites. Greater tranquility of wintering sites and improved access to food resources have benefited the vast majority of populations whose conservation status was unfavorable.

Among ducks and coots, ten species are increasing significantly, such as brent goose, greylag goose, shoveler, and gadwall, seven are declining (such as tufted duck, pochard, and pintail), four are stable (pintail, pochard), and nine are considered as having no clearly defined trend, such as whooper swan or bean goose.

All wader populations have increased since 1980, except for ruff and oystercatcher, which remain stable. They benefit from low disturbance and protection of large coastal wetlands with over two-thirds of counted individuals in protected areas (grey plover, curlew sandpiper, black-tailed godwit, redshank). This increase is all the more significant as France hosts a substantial share of biogeographic populations of certain species, as mentioned previously.

• Monitoring of wintering waterfowl has been conducted every year for over forty years. Counts are conducted in mid-January, at the height of winter when wintering populations move the least (outside cold spells). These counts, coordinated nationally by the League for the Protection of Birds, are part of an international monitoring program under Wetlands International. In France, approximately 1,500 sites represented on the map below are monitored. These are grouped into nearly 400 functional sites, coherent site collections such as a river section, a marsh, a group of ponds, or a network of lagoons. • For this study focusing exclusively on the coastline, a selection was made from these functional sites. Only 90 of them located within 10 kilometers of the coast were included.

• Ducks and coots: geese, ducks, swans, geese…; • Waders: sandpipers, godwits, sandpipers, curlews, plovers…; • Gulls: gulls, terns, gulls, and terns; • Herons: egrets, storks, flamingo, common crane, and herons; • Divers and grebes: great crested grebe, little grebe, arctic diver, black-throated diver…; • Cormorants: great cormorant and shag; • Rails: coot, crakes, and water rail.

• The associations and organizations participating in counts 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 network of Reserves; C.C. Pays d'Iroise; C.E.N. Corsica; C.E.N. of Provence; C.G. Gironde; C.G. Haute-Corse; C.G. Morbihan; C.O.R.A. Ain; C.O.R. Ile-de-France; C.E.N. Poitou-Charentes; Ornithological Center Lorrain; Charente Nature; Ornithological Club of Gers; Local Committee 65; CEN Languedoc-Roussillon; Coastal Conservancy; 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. of Deux-Sèvres; G.O. of Roussillon; G.O. and Naturalist of Nord-Pas-de-Calais; Norman G.O.; Sarthois Ornithological Group; Indre Nature; LE RENARD; Naturalists of Hérault; Loiret Nature Environnement; LPO Alsace; LPO Anjou; LPO Aquitaine; LPO Ardèche; LPO Aude; LPO Audomarois; LPO Auvergne; LPO Brenne; LPO Champagne-Ardennes; LPO Charente-Maritime; LPO Cher; LPO Côte-d'Or; LPO Drôme; LPO Franche-Comté; LPO Upper-Normandy; LPO Upper-Savoy; LPO Hérault; LPO Ille-et-Vilaine; LPO Isère; LPO Loire; LPO Loire-Atlantique; LPO Marais Breton; LPO PACA; LPO Network Reserves; LPO Rhône; LPO Savoy; LPO Tarn; LPO Touraine; LPO Vendée; LPO Vienne; LPO Yonne; LPO BirdLife France; Maison de l'Estuaire; Mayenne Nature Environnement; Museum Toulon; Natur-Essonne; Naturalists 34; Nature 18; Nature Midi-Pyrénées; ONCFS - CNERA Migratory Avifauna; ONCFS/SD 13; ONCFS/SD 22; ONCFS/SD 29; ONCFS/SD 33; ONCFS/SD 44; ONCFS/SD 56; ONCFS/RNCFS Morbihan Gulf; ONCFS/Chanteloup Station; ONCFS/Waterfowl Network/F.D.C.; OBIOS; Marquenterre Park; P.N.R. Boucles Seine Normande; P.N.R. Gascony Moors; P.N.R. Narbonnaise in Mediterranean; P.N. Iroise Marine; Picardie Nature; P.O. of Teich; R.N.N. of Banc d'Arguin; R.N.N. of Bay of Saint Brieuc; R.N.N. of Bay of Aiguillon 17; R.N.N. of Bay of Aiguillon 85; R.N.N. of Bay of Somme; R.N.N. of Chérine; R.N.N. of Marais de Séné; R.N.N. of Beauguillot; R.N.N. of Bagnas; R.N.N. of Biguglia; R.N.N. of Bruges; R.N.N. of 7 Islands; R.N.N. of Müllembourg; R.N.N. of Ramières; R.N.N. of Cousseau; R.N.N. of Marais d'Orx; R.N.N. of Val d'Allier; R.N.N. of Estuary of the Seine; R.N.N. of Iroise Sea; R.N.N. of Lilleau of Snow; R.N.N. of Moëze; R.N.N. of Saint-Denis-du-Payré; R.N.N. of Marais d'Yves; Birdwatch Network 65; S.E.P.A.N.S.O.; S.E.P.O. Limousin; SIAGM/Morbihan Gulf PNR project; SYMEL; S.N.P.N./R.N. of Grandlieu; S.N.P.N./R.N. of Camargue; S.O.B.A./Nature Nièvre; Soc. Sci. Nat. Tarn-et-Garonne; Sologne Nature Environnement; Tour-du-Valat Biological Station. • Source: League for the Protection of Birds (LPO) Author: Data and Statistical Studies Department (SDES) and LPO Written: November 2017, updated