It is easy to find crags almost everywhere in Navarre, although the greatest number and the most spectacular representatives are to be found in the community?s mountainous regions such as the north-west (Urbasa, Lokiz, Codés, Aralar, Andia), the Pre-Pyrenees and the Pyrenees themselves. In these areas, most of the cliffs consist of limestone greatly eroded by water, while in the southern half, it is more common to find gypsum and clay.
The Pre-Pyrenean area is worthy of particular mention thanks to the abundance of ravines (Foz) with large rock faces which attract specialised birds. The best known of these are the Foz de Lumbier, Foz de Arbayun and Foz de Burgi.Birds:
Cliffs make for a highly interesting environment: the great number of cavities that they house provide excellent refuge for numerous birds and the fact that they are hard to access and subject to strong winds means that not only are they safe, but they also provide large birds of prey with the currents they need in order to gain height in flight.
Rock faces, therefore, are mainly used as places of refuge and for breeding purposes, while food is sought in the surrounding area.
The most striking species are, without doubt, the birds of prey. The Egyptian Vulture, Griffon Vulture, Lammergeier, Golden Eagle, Peregrine Falcon and Common Kestrel breed on the shelves. Bonelli?s Eagle is very rare. Nocturnal birds of prey include the Barn Owl, Little Owl and Eagle Owl.
There are, however, other less conspicuous, but nonetheless interesting birds such as the Alpine Swift, Rock Dove, Crag Martin, House Martin, Rock Thrush, Blue Rock Thrush, Black Redstart, Red-billed Chough, Common Raven, Eurasian Jackdaw and Rock Sparrow.
During the winter, it is also possible to spot the Wallcreeper and the Alpine Accentor on a good part of the rock faces in areas lower than those of the high mountain.