The Parque Natural los Marismas de Odiel comprises beautiful marshland that is habitat for over two hundred species of birds. It is located on the River Odiel on the western side of Huelva. The birds include spoonbills, egrets, stilts and little terns. The wetlands have been declared a World Biosphere Reserve. At the La Calatilla Visitor Centre there is an exhibition about the marshlands and you can obtain information about walks.