An area of limestone cliffs and several large gorges. The vegetation includes alpine grassland, scrub, and Quercus, Fagus and Pinus forests. The main human activities are forestry, hunting and livestock-grazing.
This is an important site for cliff-nesting birds and a wintering site for Perdix perdix. The site holds the largest Gyps fulvus colonies in Spain.
BirdLife International (2019) Important Bird Areas factsheet: Leyre, Illón and San Miguel mountain ranges. Downloaded from http://www.birdlife.org on 26/08/2019.