Guano

Guano (Quechua, huanu, “dung”), dried excrement of certain vertebrates, particularly seabirds, valued as fertilizer. The Peruvians have used guano since before the Spanish conquest. One of their sources of supply was the Chincha Islands, off the southern coast of Peru. These islands and the Lobos groups off northern Peru were breeding grounds for seabirds, whose accumulated droppings resulted in piles of guano often more than 30 m (100 ft) high.

In 1804 a visitor to Peru took some guano to Europe. Its value as a fertilizer soon became widely known, and by 1850 the Peruvians had begun to export it in large quantities. Other sources of guano, such as Mexico, Chile, and various Pacific islands, were used as the Peruvian supply dwindled. The dried faeces of other creatures also came into use as guano, particularly from bats, found in caves in New Zealand and the United States. The term guano is sometimes applied to other organic fertilizers; for example, the dried and powdered bodies of certain fish are often called fish guano.