The upper valleys of La Jacetania are covered in forest and “seas of cloud”, with stands of beech and fir trees, but there are also mountain pines and subalpine forests of black pine, along with Atlantic pastures, peatlands, cliffs and mountain lakes.

At lower altitudes, in then transition area between Eurosiberian and Mediterranean territories, forest of holm oak and pine give away on the plains to farmland and hay fields, nearly always surrounded by hedgerows, which improve them biologically. Little by little the oak trees gain ground accompanied by their usual aromatic scrub, reminding us of the Mediterranean enviroments that also flourish in this area. Sheltered by hedgerows and riverside vegetation, many streams and rivers empty theis waters into the River Aragon, at times carving out impressive gorges or ravines, which dwarf the visitor, but undoubtedly make the birding that much richer. Hence, there es a real mosaic of forest and transitional scenery providing a home for no less than 206 bird species, including those that spend the whole year in La Jacetania, those that summer or winter in the region, as well as those just passing through on migration.

Many birds inhabit the forests of La Jacetania, though woodpececkers, passerines and thrushes take centre stage in these ecosystems. Some remain all year, while others visit only in the summer, but they all live and forage for food in the forest.