Spaces devoid of any trees but with the ground covered by extensive areas of crops, pasture or scrubland also provide an important ecosystem for certain species of bird. In La Jacetania, the Pyrenean depression of the Berdún Canal is crossed by the River Aragon. It is the prime example of this type of environment, dominated by human activities devoted to grazing and farming on land that is loamy and generally flat.

The Berdún Canal provides food for a large proportion of the species that come down from the peaks and high valleys with the onset of the cold season and fewer insects, to visit the farmlands in search of seeds and milder temperatures.

The abandonment of farms has led to the simplification of agricutural landscapes and a resulting loss of biodiversity. Given the importance of these areas, it is essential that they should be conserved and preserved as the life-supporting environments that they are. Hence importance of policies that aim to maintain the lrge farms, which tend to reconcile such activities by conserving biodiversity and encouraging the active participation of all the sectors concerned. Key elements contributing to the excellent quality of these sites are the presence of levestock, crop rotation, fallow periods, the farming of leguminous species, the maintenance of boundaries as fringe habitats for all types of wildlife, environmental farming practices, the continuation in the area of livestock barns and farm buildings, the delay in harvesting, sustainable techniques for harvesting and the conservation of scattered woodland.

For instance, the Montagu’s Harrier builds its nest on the ground among the crops, generally in unirrigated fields sown with cereals. The density of the crops hide it from view, making it invisible to potential predators. The mechanisation of harvesting procedures in recent decades has resulted in high mortality rates for the chicks whisch are hit by the machices before they are ready to fly. Therefore, in order for this species to survive, it is advisable to grow cereals with a longer cycle so that the birds are already flying when the crops are harvested. Species such as Crested Lark, Nothern Wheatear, Red-backed Shrike, Corn Bunting, Marsh and Montagu’s Harrier, Black and Red Kites, Common Swift, Crows and Little Owl inhabit this environment, making it relatively easy to see and hear them here.