The roots of United States imperialism are unfamiliar to most of us. Few would guess that this territory acquisition began with guano. Yup—bird poop. Specifically, bird poop to provide a replacement for guano found on islands offshore from Peru, recognized by the ancient Andeans as a valuable fertilizer for thousands of years.
In the 1800s, intensive agriculture had seriously depleted soil fertility in many parts of the world, including along the East Coast of the United States. Guano became a prized fertilizer that could double and even triple crop yields. Enormous deposits of guano on the Chincha Islands of Peru were mined and shipped to England, France, Germany and the United States beginning in the 1840s. By the 1850s, the U.S. was importing around 760,000 tons of guano annually.
Guanay cormorant colony on South Chincha Island, Peru in 1907 (Wikimedia)
Why Guano?
Bird excrement is a highly effective fertilizer, as it contains significant amounts of nitrogen, phosphate, and potassium, all nutrients essential for plant growth. Cold Pacific Ocean currents flowing along the west coast of South America support rich marine resources, including millions of cormorants, pelicans, gulls, and other seabirds that feed on the abundant fish in the nutrient-rich water. These birds nest on offshore islands that have no predators. An arid climate, with little precipitation, preserves tremendous amounts of guano, including the high elemental content of nitrogen in the manure. For millennia, the Indigenous Andean people harvested the guano found on the island nesting grounds. (My post Food, Fertilizer, and Inca Empire Conservation describes the importance of this resource to ancient Andeans.)
The value of South American guano was first recognized in Europe after the Prussian geographer and explorer, Alexander von Humboldt, encountered it in 1802 in Peru. The impressive fertilizing properties of the Chincha Islands guano astonished him, and his writings about this topic reached many Europeans. Ships that carried consumer goods such as textiles and flour to Peru, or gold miners to California, carried loads of Peruvian guano back to Europe and the East Coast of North America, creating a significant source of revenue for Peru.
Newspaper advertisement for Alta Vela Guano Co. fertilizer as published in The Star and Sentinel (Gettysburg, Pennsylvania on September 18, 1868. Alto Velo is a small island in the Caribbean Sea, now part of the Dominican Republic. (Wikimedia)
To control prices and help to ensure adequate supplies, Congress passed the Guano Islands Act, signed into law by President Franklin Pierce in 1856. This act directed the country to secure access to guano by claiming sovereignty over any ostensibly unclaimed and uninhabited territory containing this natural resource. The rush to acquire guano—and new lands—began. The newly claimed territories marked America’s first effort to gain lands overseas; essentially, the beginning of the United States empire.
Entrepreneurs lost no time in seeking and claiming over 100 small islands and atolls (ring-shaped islands with a coral reef rim that encircles a lagoon) where birds gather, and guano could be harvested in the Pacific Ocean and the Caribbean Sea. When the guano bonanza ended, several of these islands took on new roles. Today, the Guano Islands Act continues to be a law, and ten islands remain in the United States’ possession. Some of these islands have interesting histories.
Islands in the Middle of Oceans
Many of the territories claimed under the Guano Islands Act yielded little or no guano, nonetheless, other uses of economic importance were found. Mid-ocean islands that are attractive to birds for resting and feeding places could also serve for ships and aircraft. Between 1935 and 1941, pilots used Midway Atoll as a refueling stop for flying boats operated by Pan American Airlines. Howland Island is best known as the planned stopover that Amelia Earhart and Fred Noonan failed to reach when they and their airplane disappeared on July 2, 1937.
Beginning in the 1930s, American leaders recognized the strategic importance of many islands, designating the U.S. Navy and Air Force as administrators. Following the bombing of Pearl Harbor in 1941, the Imperial Japanese Navy also attacked many of these Pacific Island territories. The United States military hastily constructed additional airfields and supply stations, sometimes by dredging reef coral and using it as fill material to create more space. Two islands gained particular significance—Midway Atoll and Johnston Island.
Midway Atoll
Midway Atoll lies near the northwestern end of the Hawaiian chain of volcanic islands, about 1,310 mi (2,220 km) northwest of Honolulu. In 1859, Captain N.C. Brooks claimed the atoll for the United States under the Guano Islands Act. There are no records of attempts to mine guano on the island. The U.S. Navy administered the atoll for many years as a refueling stop for transpacific flights, for Navy ships, and as a submarine base.
Midway was considered second only to Pearl Harbor in importance to protect the U.S. West Coast. Six months after Japan’s attack on Pearl Harbor, the Battle of Midway took place near the atoll from June 4 to 7, 1942. During the horrific and decisive battle, the U.S. forces managed to sink four Imperial Japanese Navy aircraft carriers and hundreds of Japanese aircraft. Many consider the Battle of Midway to be the beginning of the end of the Japanese Navy’s control of the Pacific Ocean.
Later, Midway was used to support the Korean War and the Vietnam War, with ships and aircraft stopping for refueling and emergency repairs. U.S. Navy operations on Midway were formally closed in 1993, although the Navy continued responsibility for cleaning up environmental contamination.
Aerial photo of Midway Atoll, 2008, by U.S. Fish and Wildlife Service (Wikimedia)
Johnston Island
Located in the North Pacific Ocean about 860 mi (1,390 km) southwest of the island of Hawaii, Johnston Island was claimed as an American territory in 1858. Later, between 1958 and 1963, the military used Johnston Atoll as a nuclear weapons test site with megaton hydrogen bombs. Missile launch failures severely contaminated the island and surrounding areas with weapons-grade plutonium, and heavily damaged the Johnston Island launch complex. Cleanup operations included dumping plutonium-contaminated debris into the ocean surrounding the island. The atoll then became a test site for biological warfare, along with satellite tracking systems that were operated on the island until 1975.
Johnston Island became a chemical weapons storage site in 1971, including holding bulk 1-ton containers of Sarin and mustard gas. The military also stored Agent Orange, used as part of the U.S. herbicidal warfare program during the Vietnam War. Leaking barrels and spills that occurred during re-drumming operations contaminated the storage areas and the lagoon with herbicide residues. Incineration of the massive amounts of chemical weapons on the island began in the 1990s. This work was considered complete by 2003, and allegedly environmentally remediated. The efforts included burying radioactive soil and debris in a landfill with a 24-inch (61 cm) cap of coral. (Effective? We can hope….)
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Americans claimed over 100 islands under the Guano Islands Act, however, competing claims from various countries and other actions now result in only ten remaining as U.S. possessions. Ownership of a few islands continues to be disputed. The U.S. Fish and Wildlife Service, Department of the Interior, administers the territories as National Wildlife Refuges. Although human activities have decimated their numbers, seabirds still visit and nest on the islands.
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Fascinating! Was the bird population fairly constant or was it seasonal? Just wondering about how guano was harvested while all the birds inhabited the island?
Good questions – thanks! From what I have read, the Incas oulawed disturbance of birds during the breeding season, which allowed a sustainable use of guano since the birds continued to thrive. Once the entrepeneurs of the 1800s arrived, however, workers trampled nests and birds in the race to harvest the guano — and after a few years, the guano supplies were depleted and bird numbers were greatly reduced.
Thanks. Sounds like short term greed destroyed this resource.