Urdaibai

Urdaibai is organised around the River Oka, which on its way to the Bay of Biscay opens into an estuary some twelve kilometres long of sandbanks, marshes and river flats ringed by low summits. It covers 21,774.78 hectares on land and 269.24 at sea in the Biscayan district of Busturialdea, and its boundaries run from Mount Oiz in the south to Cape Matxitxako in the west and Arbolitz point in the east, with the island of Izaro as its northern limit. In extent and state of conservation it is the most important wetland in the Basque Country and a key resting and wintering point for migratory birds that are scarce in the peninsula, such as spoonbill, grey heron, cormorant and tern, along with large concentrations of waders.

Its designation as a Biosphere Reserve came on 6 December 1984 and was largely the fruit of public mobilisation: in 1968 the provincial council had commissioned a Special Plan for the Development of the Estuary that threatened to transform it, and the public reaction eventually led the Basque Government to put the area forward to UNESCO's MaB programme. Urdaibai is also the only biosphere reserve with a law of its own governing it: Law 5/1989 of 6 July, on the Protection and Management of the Urdaibai Biosphere Reserve, which sets a specific legal regime for all its undeveloped land. To this are added the designations of Special Protection Area for Birds, wetland of international importance under the Ramsar Convention and three Special Areas of Conservation.

Unlike a conventional nature park, Urdaibai is an inhabited territory: 22 municipalities and some 45,000 people live within its boundaries, and the present landscape is the result of fifteen thousand years of human occupation. Alongside the marshes there are Cantabrian holm oak woods on limestone rock, beaches such as Laga and Laida, cliffs, and a cultural heritage that includes the chartered town of Gernika-Lumo. Management is in the hands of the Board of the Urdaibai Biosphere Reserve.