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Location Belgium, Vlaams Gewest
Central coordinates 3o 21.00' East  51o 20.00' North
IBA criteria B1i, B3, C3, C6
Area 1,820 ha
Altitude 0 - 7m
Year of IBA assessment 2000

BirdLife Belgium

Site description An area of saltmarshes and mudflats (a remnant of a former estuary) with a dune system and polders with halophile creeks and grasslands, several reedbeds and canals fringes with reed. The dune and saltmarsh area extends across the border into the Netherlands.

Key Biodiversity The site supports internationally important numbers of wintering geese. Significant numbers of gulls, terns and meadow birds also breed and the dunes are an important staging site for migrating passerines.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Pink-footed Goose Anser brachyrhynchus winter  500 individuals  good  B1i, C3  Least Concern 
Greater White-fronted Goose Anser albifrons winter  10,000 individuals  good  B1i, C3  Least Concern 
Western Marsh-harrier Circus aeruginosus breeding  1995  4 breeding pairs  good  C6  Least Concern 
Pied Avocet Recurvirostra avosetta breeding  41 breeding pairs  B3, C6  Least Concern 
Mediterranean Gull Larus melanocephalus breeding  1996  28 breeding pairs  good  C6  Least Concern 
Common Tern Sterna hirundo breeding  1995  62 breeding pairs  good  C6  Least Concern 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Het Zwin Nature Reserve 125 protected area contained by site 125  
Zwin Wetlands of International Importance (Ramsar) 530 protected area contained by site 530  


IUCN habitat Habitat detail Extent (% of site)
Forest   -
Coastline Mud flats & sand flats; Salt marshes; Sand dunes & beaches  10%
Artificial - terrestrial Arable land; Forestry plantations; Perennial crops, orchards and groves  80%

Land use

Land-use Extent (% of site)
agriculture 70%
nature conservation and research 15%
tourism/recreation 5%

Protection status National Low International High125 ha of IBA covered by Nature Reserve (Het Zwin, 125 ha). 1,820 ha of IBA covered by Special Protection Area (Het Zwin, 1,820 ha). 530 ha of IBA covered by Ramsar Site (Zwin, 530 ha).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Zwin. Downloaded from on 27/10/2016

To provide new information to update this factsheet or to correct any errors, please email BirdLife