Placed since 1973 under the protection of LIPU (Italian Bird Protection Association) it represents a resting place and a fundamental stop during the route of the migratory birds. It becomes Special Nature Regional Reserve since 1987 and is managed by the Natural Park. It is the main humid area of the southern Piedmont constituted by the artificial lakes of Crava and Morozzo realized for the exploitation of the waters from the streams Pesio and Brobbio. The lakes have created a great extended natural humid environment, which has favoured the development of biodiversity on faunal and vegetal level.