Guano has been harvested over several centuries along the coast of Peru, whereislands and rocky shores have been sheltered from humans and predators. The Guanay Cormorant has historically been the most important producer of guano; its guano is richer in nitrogen than guanofrom other seabirds. Other important guano producing species off the coast of Peru are the Peruvian Pelican and the Peruvian Booby.
Advertisement for guano, 1884In November 1802,Alexander von Humboldt studied guano and its fertilizing properties at Callao in Peru, and his subsequent writings on this topic made the subject known in Europe.
The high concentration of nitratesalso made guano an important strategic commodity. The War of the Pacific (1879 to 1883) between the Peru-Bolivia alliance and Chile was primarily based upon Bolivia's attempt to tax Chilean guanoharvesters and over control of a part of the Atacama Desert that lies between the 23rd and 26th parallels on the Pacific coast. The discovery during the 1840s of the use of guano as a fertilizer and itsChile saltpetre content as a key ingredient in explosives made the area strategically valuable.
In this context the US passed the Guano Islands Act in 1856 giving citizensdiscovering a source of guano the right to take possession of unclaimed land and entitlement to exclusive rights to the deposits. However, the guano could only be removed for the use of citizens of the UnitedStates. This enabled US citizens to take possession of unoccupied islands containing guano.
By the end of the 19th century, the importance of guano declined with the rise of artificial...