Bird droppings accumulated over hundreds of years that gained popularity as a fertilizer in the nineteenth century and became a leading trade item in both Europe and America.
The native populations of South America used guano, originally called huano, a Spanish word for the dried excrement of seafowl, as a fertilizer for thousands of years. The rocky barren islands off the coast of Peru proved the richest source for guano. Coastal Peru’s climate—of cold water flowing from the equator and meeting Peru’s warm air, which inhibited rainfall—allowed guano to solidify in a dry climate while preserving its nutrients. The coastal waters drew huge numbers of migratory birds, including the guanay cormorant, gannets, gulls, and pelicans that rested on the islands free from predators. Over time, these birds produced guano as deep as 150 feet.
The Peruvian government recognized the value of guano and kept tight control of the commodity with high prices. In 1830, the Peruvians exempted guano from taxation, since it was important to Peruvian agriculture, fostering a local market, but an international market did not develop until 1840, when it was introduced in England on a large scale. As journals, newspapers, and almanacs praised guano as a fertilizer and as its popularity grew, English farmers found that their yields increased between 30 and 300 percent. Unlike other fertilizers, guano was more soluble, performed well in heavy and light soils, and was rich in both nitrogen and phosphate. It was also versatile and had positive effects on a broader range of crops than other fertilizers.
Extracting guano was no easy task. During the day, guano baked into a solid mass that required picks and shovels to break it loose. Most of the miners were indentured servants, convicts, military deserters, kidnapped Peruvians, and slaves who worked twenty-plus hours a day digging trenches 60 to 100 feet deep. The chunks of guano were then hauled by wheelbarrow to a canvas chute that went directly into a ship’s hold. The working conditions often made the workers ill. Also, the dust produced by guano was inhaled by workers and caused many respiratory and gastrointestinal problems.
As the English market grew, prices declined and the English merchants began to look to the United States as a potential customer. American farmers were eager to try the fertilizer, and when they did, their yields increased as did the demand for guano. American farmers became increasingly unhappy with the high prices and began to petition the U.S. government to help keep prices down. In response, the United States tried to negotiate a free-trade agreement with Peru, but was unsuccessful.
In the absence of a free-trade agreement, the United States drafted and passed the Guano Island Act of 1856, which allowed American citizens to take possession of areas not under the lawful jurisdiction of other nations. As a result, American entrepreneurs claimed any piece of land with guano. Approximately ninety-four islands, rocks, and keys were claimed under the Guano Island Act, and sixty-six of them were recognized by the U.S. State Department as American acquisitions, including the islands of Howland, Baker, and Jarvis, as well as some Caribbean islands. As artificial fertilizers were developed in the late 1800s, the demand for guano lessened. In Peru during the height of demand for guano (1840–1880), an estimated 20 million pounds was excavated for export and generated $2 billion in profit. As the guano market declined, the United States returned most of the acquisitions.
By 1910, Peru’s guano islands were severely depleted and the economy was suffering. In an effort to conserve the remaining guano reserves, the Peruvians established the Guano Administration to preserve the guano, the birds, and the environment. Islands were designated off limits for six months to allow birds to raise young and replenish the reserves without interference from humans. Steps were also taken to manage the fishing industry so the guano-producing birds would remain attracted to the area, and bird preserves were established on the mainland.
Lisa A. Ennis
See also: Fertilizer.
Mathew, W.M. “Peru and the British Guano Market, 1840–1870.” Economic History Review (New Series) 23, no. 1 (April 1970): 112–128.
Skaggs, Jimmy M. The Great Guano Rush: Entrepreneurs and American Overseas Expansion. New York: St. Martin’s Press, Griffin, 1994.
“TED Case Studies: Guano Trade.” Trade and Environment Database (www.american.edu/TED/guano.htm, accessed April 2004).