The prosperity of the Chincha Kingdom – a powerful ancient society on the coast of Peru – was largely thanks to their savvy use of bird poop, according to a study recently published in PLOS One.
Archaeological analysis of maize (corn) from burial tombs revealed that the Chincha people likely used seabird poop, or ‘guano’, as a fertiliser to supercharge their agriculture.
The poop enabled the Chincha Kingdom to grow a surplus of maize and therefore expand their economy, population and influence, until they became one of the most prosperous and influential pre-Inca societies in South America.
“Seabird guano may seem trivial, yet our study suggests this potent resource could have significantly contributed to sociopolitical and economic change in the Peruvian Andes,” said lead author Dr Jacob Bongers, from the University of Sydney. “In ancient Andean cultures, fertiliser was power.”
Bongers’ team analysed 35 maize samples from burial tombs in the Chincha Valley – at the time, home to an estimated 100,000 people – and found the maize contained exceptionally high levels of nitrogen.
Seabird poop is especially rich in nitrogen because of the birds’ marine diets, so this biochemical evidence suggests the Chincha people used the guano to enrich their soils.
“The guano was most likely harvested from the nearby Chincha Islands, renowned for their abundant and high-quality guano deposits,” Bongers explained.
The researchers also examined contemporary imagery of seabirds, fish and sprouting maize on ceramics, pottery, wall carvings and paintings.
This, they said, was further evidence that seabirds and maize were associated with each other and held cultural importance in Chincha society.
“Together, the chemical and material evidence we studied confirms earlier scholarship, showing that guano was deliberately collected and used as fertiliser,” said Bongers.
“But it also points to a deeper cultural significance, suggesting people recognised the exceptional power of this fertiliser and actively celebrated, protected and even ritualised the vital relationship between seabirds and agriculture.”
Much of the history of the Chincha Kingdom remains unknown – including when it began – but we do know that it became part of the Inca Empire around 1480 AD, around half a century before the Spanish conquest of Peru.
Until then, the Chincha traded with the Inca, who were famously obsessed with maize and used it to make their ceremonial fermented beer, called ‘chicha’.
But the Inca couldn’t grow much maize themselves because they lived in the highlands of the Andes mountains, and so didn’t have access to precious bird poop.
“The true power of the Chincha wasn’t just access to a resource; it was their mastery of a complex ecological system,” said study coauthor Dr Jo Osborn, from Texas A&M University.
“They possessed the traditional knowledge to see the connection between marine and terrestrial life, and they turned that knowledge into the agricultural surplus that built their kingdom.”
“Their art celebrates this connection, showing us that their power was rooted in ecological wisdom, not just gold or silver.”
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