Sado estuary

Year of compilation: 2000

Site description
A large estuary with extensive mudflats and saltmarshes, located in central Portugal, c.50 km south of Lisbon. Setúbal is the main town in its vicinity. The inner part of the estuary is bordered by rice-fields and reedbeds, whereas the north-western limits are densely populated and the south-western parts are sheltered from the open sea by a sandbar.

Key biodiversity
Several waterbird species (mainly waders) occur in winter in large, internationally significant numbers, and the site holds 20,000 or more wintering waterbirds on a regular basis. There are also important numbers of breeding waterbirds, notably Himantopus himantopus and Sterna albifrons. The rice-fields are an important feeding ground for the egrets and herons from the nearby breeding colony at Murta dam (024). More than 500,000 Columba palumbus roost within the IBA in winter.

Pressure/threats to key biodiversity
Over 30% of the available area of saltpans has been transformed into fish-farms in the course of the last ten years. There are plans for large-scale dredging at the mouth of the estuary that may affect water-flow and sediment deposition inside the estuary, thus indirectly affecting the bird community.

Protected areas
National Partial International High20,011 ha of IBA covered by Nature Reserve (Estuário do Sado, 23,971 ha). 24,633 ha of IBA covered by Special Protection Area (Estuário do Sado, 24,633 ha). IBA also overlaps with Ramsar Site (Estuário do Sado, 25,588 ha).

Recommended citation
BirdLife International (2022) Important Bird Areas factsheet: Sado estuary. Downloaded from on 17/01/2022.