Sado estuary

IBA Criteria

Year of most recent IBA criteria assessment: 2002

Populations of IBA trigger species
Species Current IUCN Red List Category Season Year(s) of estimate Population estimate IBA Criteria Triggered
White Stork Ciconia ciconia LC resident 1996 50-70 breeding pairs C6
Common Little Bittern Ixobrychus minutus LC breeding 1996 common C6
Purple Heron Ardea purpurea LC breeding 2002 15 breeding pairs B2, C6
Little Egret Egretta garzetta LC non-breeding 1996 common C6
Great Cormorant Phalacrocorax carbo LC winter 1996 1,000-2,200 individuals B1i, C3
Pied Avocet Recurvirostra avosetta LC winter 1996 2,000-4,000 individuals A4i, B1i, B2, C2
Black-winged Stilt Himantopus himantopus LC breeding 1996 200-800 breeding pairs A4i, B1i, C2, C6
Black-tailed Godwit Limosa limosa NT winter 1996 2,000-11,000 individuals B1i, C3
Dunlin Calidris alpina LC winter 1996 12,000-16,000 individuals B1i, B2, C3
Collared Pratincole Glareola pratincola LC breeding 1996 5-20 breeding pairs C6
Little Tern Sternula albifrons LC breeding 1996 50-100 breeding pairs B2, C6
Western Marsh-harrier Circus aeruginosus LC resident 1996 5-6 breeding pairs C6
A4iii Species group - waterbirds n/a winter 1996 20,000 individuals A4iii, C4

Note: This table presents the IBA criteria triggered and the species that triggered then at the time of assessment, the current IUCN Red List category may vary from that which was in place at that time.

For more information about the IBA assessment process and criteria please click here

IBA Protection

Protected Area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)
Estuário do Sado Special Protection Area (Birds Directive) 24,633 protected area overlaps with site 24,312
Estuário do Sado Ramsar Site, Wetland of International Importance 25,588 protected area overlaps with site 24,633
Estuário do Sado Site of Community Importance (Habitats Directive) 30,968 protected area overlaps with site 23,346
Estuário do Sado Reserva Natural 23,971 protected area overlaps with site 20,011
Comporta / Galé Site of Community Importance (Habitats Directive) 32,051 protected area is adjacent to site 0
Açude da Murta Special Protection Area (Birds Directive) 498 protected area overlaps with site 0


IUCN Habitat Habitat detail Extent (% of site)
Forest Mixed woodland, Broadleaved evergreen woodland -
Shrubland Sclerophyllous scrub, garrigue and maquis -
Wetlands (inland) Standing freshwater, Water fringe vegetation -
Artificial/Terrestrial Arable land, Forestry plantations, Other urban and industrial areas -
Coastline Sand dunes & beaches, Salt marshes, Mud flats & sand flats, Lagoons, Tidal rivers & enclosed tidal waters -
Marine Neritic -
Marine Intertidal -
Marine Coastal/Supratidal -
For further information about the habitat classification please click here.

Land use

Land-use Extent (% of site)
agriculture -
fisheries/aquaculture -
forestry -
hunting -
nature conservation and research -
tourism/recreation -
urban/industrial/transport -
For further information about the land use classification please click here.

Recommended citation
BirdLife International (2023) Important Bird Areas factsheet: Sado estuary. Downloaded from on 06/02/2023.