An Atlantic estuary on the Basque coast, protected for its wetlands, woodlands, and migratory birds.
Urdaibai Biosphere Reserve
Urdaibai Biosphere Reserve is a protected coastal and estuarine landscape in the Busturialdea region of Biscay, in the Basque Country of northern Spain. Designated by UNESCO in 1984, it centers on the estuary of the Oka River, which flows through Gernika and empties into the Cantabrian Sea between the towns of Bermeo and Mundaka. The reserve combines a tidal estuary, broad sand flats, Atlantic cliffs and islands such as Izaro, and a ring of low green mountains including the slopes of Mount Oiz.
The ecological heart of Urdaibai is its marshland, the largest and best preserved in the Basque Country and one of the most important wetland complexes on the Cantabrian and Atlantic coast of the Iberian Peninsula. Together with the Marismas de Santoña it forms a key refuge for migratory birds and an internationally recognized wintering site for waterfowl along the East Atlantic Flyway. Cantabrian oak forests of holm oak and strawberry tree, Atlantic oak woodlands, planted conifer forests, and karst limestone hills create a striking diversity of nearby habitats.
Beyond its natural value, Urdaibai encompasses a deeply human landscape of pre-Roman and Roman heritage, fishing villages, surf-famous beaches, and the symbolic town of Gernika, home to the Tree of Gernika and the historic Basque parliament. The reserve balances conservation with active farming, forestry, fishing, and tourism, and is governed through a dedicated management plan and a Patronato that coordinates research, education, and sustainable development across the 22 municipalities that share its territory.
