In the 19th century, a healthy fraction of the worlds attention revolved around poop. More specifically, bird turd islands.

From a modern frame of reference, this certainly raises a few questions:

1. Were people in the 19th century ok?
   Probably not.
   
2. Will bird poop raise my car’s resale value?
   No.
   
3. Should I be investing in guano instead of gold?
   This blog does not give investment advice.

So what gives, why the poop obsession?

People Need to Eat

Guano had value in the 19th century because fertilizer was in short supply. Plants need nutrients like nitrogen, phosphorus, and other minerals to grow, but these are often limiting in soil. Bird guano is chock full of these nutrients, thus making it an excellent fertilizer. That abundance of nutrients made guano invaluable, but its true importance only becomes clear when we remember how often famine stalked the 19th century.

We have in many ways forgotten the frequency and the deadliness of famines that predates the green revolution of 1960’s, that caused an explosion in crop yields

While there are numerous causes of famine, one key factor is low crop yields do to nutrient poor soil. This makes a good fertilizer really valuable.

This problem predates the 19th century. The bible even makes reference to value of bird guano:

The siege lasted so long that a donkey’s head sold for eighty pieces of silver, and a cup of dove’s dung sold for five pieces of silver.

2 Kings 6:25

I have no conception of what the dove dung market looked like at the time, but based on context I’m going to guess that this was an early example of poop price gouging. I personally would be willing to sell my cup of dove dung for 3 ounces of silver, though if there is collapse in silver prices I may need to reconsider this offer.

Fecal Firepower

A secondary value of guano was in the production of gunpowder. Guano is rich in calcium nitrate, which can be converted into saltpeter (KNO₃). Saltpeter acts is a principal component of black gunpowder.

Bird guano isn’t the only possible source of saltpeter, some countries have gotten creative in their quest for nitrate salts. The English of the 17th century didn’t have natural deposits of saltpeter, but a home grown method, combining urine and animal feces with with lime helped fill the need for saltpeter. Such procedures made it necessary for King Charles I to ask his subjects to:

Carefully and constantly keep and preserve in some convenient vessels or receptacles fit for the purpose, all the urine of man during the whole year, and all the stale of beasts.

Flash forward to the War of 1812. The Americans, cut off from sources of potassium nitrate in India and South America, began collecting bat guano. It was a method of sustaining the war effort, that the Confederacy replicated during the Civil War.

All Your Guano Islands Belong to Us

The social habits of sea birds, leads to large quantities of guano being deposited on small islands producing what are known as “guano islands.” Guano islands had been used for centuries by the Peruvians as fertilizer. The Prussian geographer Alexander von Humboldt collected samples of Peruvian guano, and after consulting with European analytical chemists realized how nutrient rich this guano was. This kicked off Peru’s prime position as a key player in the guano trade.

By 1850, president Millard Fillmore was not only working on trying to make it on every worst president list until the end of time, he also had bird crap on the mind. In his State of the Union that year Fillmore was clear:

Peruvian guano has become so desirable an article to the agricultural interest of the United States that it is the duty of the Government to employ all the means properly in its power for the purpose of causing that article to be imported into the country at a reasonable price. Nothing will be omitted on my part toward accomplishing this desirable end.

In 1856, Congress passed the Guano Islands Act, a peculiar piece of legislation which essentially allowed any U.S. citizen who stumbled upon an unclaimed, guano-covered island to claim it for the United States. In what some have called “America’s first imperialist experiment,” enterprising Americans fanned out across the seas looking for bird-dropping bonanzas. Over the next few decades, the US flag was planted on nearly 100 islands solely because they were blanketed in guano. Some of these guano islets such as Howland Island, Baker Island, Jarvis Island, and Navassa remain U.S. territories to this day.

The Poop Party Ends

By the late 19th century, the guano boom was beginning to bust. In Peru, mountains of guano had been mined down to the bare rock by the 1870s. Peru’s guano revenue had been so lucrative that it funded a significant part of the national budget for decades, but over-reliance on this “bird poop income” set the stage for economic trouble once the deposits ran low. Ultimately, European and American farmers began seeking out alternative options.

The dawn of the 20th century brought a dramatic turn. The German chemists Fritz Haber and Carl Bosch introduced a method to synthesize ammonia from the nitrogen in air, effectively creating synthetic fertilizer out of thin air. Lest you worry it was only used to feed people, ammonia from this process can also be used as an explosive precursor… which some have argued stretched World War I by providing Germany with a steady stream of ammonia. Haber, an ardent German nationalist during the early 1900s, would have probably viewed this as a positive, but he also thought chemical weapons were a great idea so maybe his moral compass was a little wonky. Despite his controversial role in a chlorine gas attack in Belgium in 1915 during the war, he went on to receive the 1918 Nobel Prize in chemistry for “for the synthesis of ammonia from its elements.”

While demand has waned for guano, there does remain a small guano mining operation in Peru though international exports are very limited. You can still buy sea bird guano fertilizer if that’s your cup of tea too. I also suppose you can always collect your urine, if you want to make saltpeter King Charles style, though I’m not sure you’ll ever be popular with the neighbors if you start mixing it with manure in the backyard.

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If you enjoyed this story, I highly recommend you check out The Alchemy of Air by, one of my all time favorite authors, Thomas Hager. It’s an amazing read.