A worker throws bird dung to be processed on Ballestas island, south of Lima, October 9, 2011. Ballestas, like the other 21 islands along the Peruvian coast, is home to nearly 4 million migratory birds such as guanays, boobies and pelicans whose excrement make up the world's finest natural fertilizer. The bird dung, also known as guano, reached its greatest economic importance in the 19th century as a coveted resource being exported to the United States, England and France. With a current annual production of 20 thousand tons, Peru hopes to benefit mostly small farmers by boosting organic agriculture, the Rural Agrarian Productive Development Program (Agrorural) reported. Picture taken October 9, 2011. REUTERS/Pilar Olivares (PERU - Tags: AGRICULTURE ANIMALS POLITICS ENVIRONMENT SOCIETY)