AS CAN BE SEEN ELSEWHERE IN THIS ISSUE, GUANO HAS THE power to stir men’s souls. There are virtually no lengths—or heights—to which adventurous types have not gone in pursuit of the dried excrement of bats and birds. Centuries before Columbus, Peru’s Inca rulers divided the Chincha Islands among the empire’s provinces and assigned certain times when guano could be harvested from them. They also prohibited killing the islands’ birds or disturbing them while nesting. The penalty was death.

In the mid-nineteenth century, as chemists discovered guano’s high concentration of nitrates and phosphates and as railroads spurred the development of commercial farming, guano came into great demand. A series of mad rushes ensued as guano islands were discovered, scraped clean, and abandoned. In March 1843, for example, an expedition chartered by a Liverpool businessman found guano (mostly from gannets and African penguins) to a depth of 25 feet on Ichaboe Island, off the coast of present-day Namibia. By early 1844 no fewer than 100 ships were carrying it away. The ensuing year saw an insurrection by the workers and several violent struggles for control. In January 1845 the islet was host to 450 ships and 6,000 men. By May it was deserted.

The United States got into the game in 1856 with the Guano Islands Act, which allowed American citizens to claim uninhabited guano-bearing islands as sovereign U.S. territory. More than 50 were eventually annexed. The act was a reaction to the near-monopoly enjoyed by Peru, which had the world’s best guano, thanks to dry conditions along its coast that yielded a particularly concentrated product. U.S. Navy sailors and Peruvian soldiers even fought a brief skirmish over an island claimed by both countries.

As far back as the War of 1812 guano provided saltpeter for use in gunpowder, and during the Civil War bat caves were indispensable for this purpose in the resource-poor South. Foreign guano was also a lucrative item of commerce for Northern merchants and thus a target for the Confederate navy. In 1863 the CSS Alabama took three guano ships in one month in the Atlantic. Regarding one of these, Capt. Raphael Semmes later wrote: “This ship had buffeted the gales of the frozen latitudes of Cape Horn, threaded her pathway among its icebergs, been parched with the heat of the tropics, and drenched with the rains of the equator, to fall into the hands of her enemy, only a few hundred miles from her port. But such is the fortune of war. It seemed a pity, too, to destroy so large a cargo of a fertilizer, that would else have made fields stagger under a wealth of grain. But those fields would have been the fields of the enemy, or if it did not fertilize his fields, its sale would pour a stream of gold into his coffers.”

In 1865 and 1866 Chile, Peru, and Spain fought an inconclusive war over a portion of the Andean coast that was rich in guano and minerals. In 1879 Chile defeated Bolivia in what became known as the Guano War (or War of the Pacific). The Bolivians are still sore about it. Official maps show the disputed Chilean coastline as Bolivian territory, and the country, though landlocked, maintains a navy, which is restricted to patrolling Bolivia’s half of Lake Titicaca.

By the turn of the century most large deposits of guano had been stripped, and chemical manufacturers had started switching to inorganic sources of nitrate. In San Antonio, Texas, however, a physician named Charles A. R. Campbell was using guano to fight malaria. He built a tower baited with guano to attract bats, which were meant to eat the area’s abundant malaria-spreading mosquitoes. The guano that the bats left behind in the tower was collected and sold to help pay for the project.

Campbell reported positive results for his experimental bat colony, which yielded a couple of tons of guano a year. Communities as far away as the Florida Keys tried to replicate his success, but unfortunately, no one else could toilet-train bats well enough to make them use the towers as their outhouses. Besides, examination of the guano from Campbell’s tower showed no evidence that his bats had eaten any mosquitoes; they found moths much more tasty.

Today guano fertilizer retains a niche market, selling at around five dollars a pound to organic farmers and gardeners. The irony is unmistakable: After technological discoveries first made guano wildly popular and then made it unnecessary, guano is now back in fashion as a reaction against technology.