How Bird Poop Helped Make Ancient Peru a Superpower

You probably didn’t know this, but researchers have long suspected that bird droppings may have helped nations like Peru dominate their own in ancient times. Now, science has confirmed that bird-cutting is, in fact, a kind of kingmaker.

New research published in PLOS One provides chemical evidence that guano from offshore islands fertilized corn grown by the Chincha kingdom as far back as 800 years ago, and possibly much earlier. All that said, researchers believe there is a wealth of credible evidence to suggest that an abundance of seabird harvesting supported the agriculture of these coastal civilizations, which in turn provided a wealth of political leverage.

The Humboldt Current, also called the Peru Current, is an ocean current that flows along the western coast of South America. It is cold and rich in nutrients, making it one of the most productive marine ecosystems on Earth. Fish thrive there, which of course means seabirds thrive there too.

On the rocky islands just off the coast of Peru and Chile, centuries of bird droppings piled up and turned into natural fertilizer, with all the nitrogen-rich material turning into an agricultural gold mine.

Dr. Jacob Bongers of the University of Sydney analyzed maize kernels from graves in the Chincha Valley. The crops contained elevated nitrogen levels and isotopic ratios strongly associated with seabird guano. Combined with earlier archaeological evidence, such as art depicting seabirds, fish, and sprouting corn, the chemical data confirm large-scale fertilizer use fueled by nitrogen-rich bird deposition.

In at least 1250 AD the Chinchas sailed 25 kilometers offshore to harvest guano, returning with loads to enrich their fields. This practice quickly became vital to their economy and culture as they exported surplus manure via llama caravans, generating incredible wealth.

When the Incas rose up and crushed any other neighboring civilization that dared to threaten them, the Chinchas survived. Historical accounts suggest that final incorporation into the Inca Empire was not achieved through conquest, but rather through negotiation. Access to all that rich, rich manure, fueled by bird deterrents, may be the reason. They controlled the manure; they controlled food production.

The Incas, recognizing the importance of this fertilizer, reportedly forbade island visits during seabird breeding seasons, a policy that researchers now consider an early example of conservation that demonstrates early civilizations’ understanding of the interconnectedness of life.

Of course, as they are wont to do, Europeans would later strip these islands of fertilizer and gunpowder, sparking global trade and starting wars, but long before industrial agriculture made a mess of native civilizations, there was at least one group that understood that bird deterrents have a ton of value beyond a little luck if you were to get pooped on.