Tagus Estuary Natural Reserve () is a

natural reserve A nature reserve (also known as a wildlife refuge, wildlife sanctuary, biosphere reserve or bioreserve, natural or nature preserve, or nature conservation area) is a protected area of importance for flora, fauna, funga, or features of geologi ...

Portugal Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. Featuring Cabo da Roca, the westernmost point in continental Europe, Portugal borders Spain to its north and east, with which it share ...

. It is one of the 30 areas which are officially under protection in the country. The

estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime enviro ...

of the Tagus River is the largest wetland in the country and one of the most important in Europe, a sanctuary for fish, molluscs, crustaceans, and especially to birds that stop-over on their migration between northern Europe and Africa. It is the largest estuary in western Europe, with about , and regularly hosts 50,000 wintering waterfowl.

Characterization

The Nature Reserve was established in 1976, covering an area of , characterized by an extensive surface of estuarine waters, vast fields intersected by creeks, marshes, salt flats and alluvial agricultural land (marshlands). Not exceeding above sea level and a depth of , distributed over the counties of Alcochete, Benavente and Vila Franca de Xira, the reserve falls mostly in the upstream area of the estuary of the Tagus which, with an area extending over about , is the largest in Western Europe. Around the estuary a saltmarsh has developed which is a zone of high productivity of

polychaetes Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are m ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

s and

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s, is an important breeding area for various fish species. However, it is the water birds which give the Tagus estuary its international importance. The flocks of wintering species reach up to about 120,000 individuals. The counts regularly carried out in this protected area during the winter show more than 10,000 ducks and 50,000 shorebirds. In the case of the pied avocet (''Recurvirostra avosetta''), up to 25% of the population wintering in Europe has been counted on the Tagus Estuary. The many other species present attest to the biological richness and value for nature conservation in this region: the

greater flamingo The greater flamingo (''Phoenicopterus roseus'') is the most widespread and largest species of the flamingo family. Common in the Old World, they are found in Northern (coastal) and Sub-Saharan Africa, the Indian Subcontinent (south of the Him ...

(''Phoenicopterus roseus''),

greylag goose The greylag goose (''Anser anser'') is a species of large goose in the waterfowl family Anatidae and the type species of the genus ''Anser (bird), Anser''. It has mottled and barred grey and white plumage and an orange beak and pink legs. A lar ...

(''Anser anser''), the dunlin (''Calidris alpina''), black-tailed godwit (''Limosa limosa''), hen harrier (''Circus cyaneus''),

osprey The osprey (; ''Pandion haliaetus''), historically known as sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor, reaching more than in length and a wingspan of . It ...

(''Pandion haliaetus''), bluethroat (''Luscina svecica''), common firecrest (''Regulus ignicapillus'') and Eurasian penduline tit (''Remiz pendulinus''). In the wetlands around the estuary nesting birds include red-crested pochard (''Netta rufina''), little bittern (''Ixobrychus minutus''), little egret (''Egretta garzetta'') and purple heron (''Ardea purpurea''),

marsh harrier The marsh harriers are bird of prey, birds of prey of the harrier (bird), harrier subfamily. They are medium-sized Bird of prey, raptors and the largest and broadest-winged harriers. Most of them are associated with marshland and dense reedbeds. ...

(''Circus aeruginosus''], Montagu's harrier (''Circus pyagurgus''), black-winged stilt (''Himantopus himantopus''), collared pratincole (''Glareola pratincola'') and

little tern The little tern (''Sternula albifrons'') is a seabird of the family Laridae. It was first described by the German naturalist Peter Simon Pallas in 1764 and given the binomial name ''Sterna albifrons''. It was moved to the genus '' Sternula'' whe ...

(''Sternula albifrons''). While the associated redbeds contain great reed warbler (''Acrocephalus arundinaceus''),

Savi's warbler Savi's warbler (''Locustella luscinioides'') is a species of Old World warbler in the genus ''Locustella''. It breeds in Europe and the western Palearctic. It is bird migration, migratory, wintering in northern and sub-Saharan Africa. This small ...

(''Locustella luscinioides'') and other warblers. The nearby fields have stone-curlew (''Burhinus oedicnemus'') and calandra lark (''Melanocorypha calandra'') breed on adjacent farmland.

Little bustard The little bustard (''Tetrax tetrax'') is a bird in the bustard family, the only member of the genus ''Tetrax''. It breeds in Southern Europe and in Western and Central Asia. Taxonomy The little bustard was formally described in 1758 by the S ...

(''Tetrax tetrax'') occurs all year but is more numerous in winter. Raptors which may be seen over the fields include black-winged kite (''Elanus caeruleus''), short-toed eagle (''Circaetus gallicus'') and

booted eagle The booted eagle (''Hieraaetus pennatus'', also classified as ''Aquila pennata'') is a medium-sized mostly migratory bird of prey with a wide distribution in the Palearctic and southern Asia, wintering in the tropics of Africa and Asia, with a ...

(''Aquila pennatus''). Nearby patches of woodland hold

short-toed treecreeper The short-toed treecreeper (''Certhia brachydactyla'') is a small passerine bird found in woodlands through much of the warmer regions of Europe and into north Africa. It has a generally more southerly distribution than the other European Certhi ...

(''Certhia brachydactyla''), European nightjar (''Caprimulgus europaeus''), red-necked nightjar (''Caprimulgus ruficollis''), Iberian magpie (''Cyanopica cooki'') and many passerines. During the Spring and Autumn many species stopover on the Tagus during their migration these include curlew sandpiper (''Calidris ferruginea'') in large numbers with many other shorebirds in smaller numbers,

common redshank The common redshank or simply redshank (''Tringa totanus'') is a Eurasian wader in the large family Scolopacidae. Taxonomy The common redshank was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of hi ...

(''Tringa totanus'') and black-tailed godwits reach their peak numbers during migration too. Other migrants which may be seen include

Eurasian spoonbill The Eurasian spoonbill (''Platalea leucorodia''), or common spoonbill, is a wading bird of the ibis and spoonbill family Threskiornithidae, native to Europe, Africa and Asia. The species is partially migratory with the more northerly breeding popu ...

(''Platalea alba''),

Mediterranean gull The Mediterranean gull (''Ichthyaetus melanocephalus'') is a small gull. The scientific name is from Ancient Greek. The genus ''Ichthyaetus'' is from ''ikhthus'', "fish", and ''aetos'', "eagle", and the specific ''melanocephalus'' is from ''mel ...

(''Larus melanocephalus'') and black tern (''Chlidonias niger'') and many passerines.

Conservation status

* 1976 - The Natural Reserve of the Tagus Estuary is created through Decree-Law No. 565/76. * 1980 - The reserve is designated as Wetlands of International Importance by the Ramsar Convention. * 1994 - a Special Protection Area for Wild Birds is established under Directive 79/409/EEC.

References

{{Protected areas of Portugal Nature reserves in Portugal Ramsar sites in Portugal Geography of Lisbon District Natura 2000 in Portugal Tagus