Urdaibai estuary

Urdaibai covers an area of 220 km2 (85 sq mi) with some 45,000 inhabitants, most of them concentrated in the towns of Bermeo and Gernika.

The territory is characterized by a hydrographic basin of small streams that merge in a great salt marsh surrounded by high sheer cliffs.

The surrounding countryside is occupied by meadowland, oak groves, leafy woods and specially by plantations of fast-growing conifers (Pinus radiata).

The coast is rugged and with high cliffs and some islands, of which the most important is Izaro Island.The development of forests reserves has allowed a degree of environmental conservation, which gives this area the most diverse landscape of the Basque Country.

The landscape is formed with mountains, sea and sands, which are produced by the sediments of the estuary, where marshes are flooded by the tides.

In the flysch that is made at the foot of the cliff can be found the "Arribolak", large stones which have been released from the wall and later rounded by the sea.

Human activity has substantially modified the space, but the agricultural works have allowed the recuperation of original vegetation.

The big variety of ecosystems that can be found in the Urdaibai make possible the faunistic wealth, with 318 species of vertebrates, apart from the number of different birds.

The population of the Busturialdea, which practically coincides with that of the protected Biosphere Reserve of Uradibai area is about 45,000 inhabitants are mainly located (80%), in the towns of Guernica Luno and Bermeo.

Human presence has been ongoing in the area since prehistoric times, having testimonies based on findings from the Upper Paleolithic.

It is also famous worldwide for the bombing suffered in the Spanish Civil War of 1936, the subject of Picasso's painting 'Guernica'.

The remaining populations are small centers that cater to the historical political demarcation of the Lordship of Biscay in which the call Level Earth was organized porches.

This type of interaction between man and the environment has produced the landscape of Atlantic countryside which makes up much of the area of Urdaibai.