Thousands of birds on the island of Ballestas, south of Lima, 10 October 2011. Ballestas and 21 island off the coast of Peru, is home to nearly four million migratory birds such as cormorants bougainvillea, boobies and pelicans. From bird excrement made the best natural fertilizer in the world. Bird droppings, also known as guano, reached the highest economic importance in the nineteenth century, when it began exporting to the U.S., Britain and France. Today, with annual production capacity exceeds 20 tons, Peru hopes mainly on orders from small farmers.