Celebrating 60th anniversary of SEO/BirdLife, a big spring festivalis organized in the heart of the Doñana marshes and with impresive populations of breeding migratory birds. La Dehesa de Abajo, with a colony of 400 pairs of White Stork (nesting on wild olive trees), and one of the areas with highest density of breeding Black Kite, and also others forest raptors, holds the event. The lagoon at this site (Laguna de la Rianzuela) holds also important populations of waders, ducks and herons (wintering, passing and breeding).