Bird droppings once funded Peru, sparked a war and built an American empire
In the nineteenth century, seabird droppings became one of the world's most fought-over commodities. Guano royalties turned into Peru's biggest source of revenue, the United States passed a law to claim nearly a hundred islands, and Chile went to war partly to seize the deposits.
Guano, from a Quechua word for any dung used as fertiliser, is rich in nitrogen, phosphate and potassium. Andean farmers may have gathered it from islands off Peru's desert coast for as long as 5,000 years, and the Inca rulers guarded it so jealously that disturbing the nesting birds could carry a death sentence. The guanay cormorant was always the champion producer. Europe caught on after Alexander von Humboldt studied it at Callao in 1802 and Humphry Davy's bestselling book on farm chemistry praised Peruvian guano, which stays potent because the coast is so dry.
Whaling ships returning half empty from Peru needed cargo, and in 1840 a deal between Liverpool merchants, French investors and the Peruvian state made guano a government monopoly. Some of the proceeds paid to free more than 25,000 enslaved people. Exports peaked in 1870 at over 700,000 tonnes even as the Chincha Islands, the richest source, ran low. It has even been suggested that guano shipments carried the potato blight that started Ireland's Great Famine.
The rush reshaped maps. The American Guano Islands Act of 1856 let citizens claim unclaimed islands holding deposits, and the Supreme Court later ruled such islands legally American, a decision the historian Daniel Immerwahr sees as a legal foundation of US empire. Britain, France, Germany and Japan grabbed islands too. The War of the Pacific from 1879 left Chile with Bolivia's coastline and Peru's guano islands, and Chile's treasury grew by 900 percent by 1902.
Chemistry ended the boom. From 1913, Fritz Haber's process let German factories make ammonia from the air, and demand collapsed, though organic farming has revived some interest. Bat guano has its own story, from gunpowder during the Civil War to cave ecosystems that depend on it entirely.
Source: Guano
