© George OlahAncient feathers found in the Ychsma tomb in Pachacamac, Peru. They are considered evidence of ancient trade routes over the Andes from the Amazon basin
According to lead author Dr. George Olah from ANU, the sequencing of the ancient parrot DNA has uncovered a thriving network of trade and animal transportation that connected Amazonian forests with arid communities across the Andes.
"Through combining ancient DNA sequencing, isotope chemistry and computational landscape modeling, we have been able to trace how and where these birds were moved across the landscape," Dr. Olah said.
"Our ancient habitat modeling confirmed that the western side of the Andes was just as inhospitable to these species one thousand years ago as it is today. These parrots are strictly rainforest dwellers with a natural home range of around 150 kilometers. The fact that they ended up more than 500 kilometers away, on the other side of South America's highest mountain range, proves human intervention. They do not naturally fly over the Andes."
© Balazs TiszaRed-and-green macaws are native to the Amazon basin.
The research team's findings show that several species of Amazonian macaw parrots — native to the lowland rainforest just east of the Andes — were captured in the wild, carried high over mountain passes and kept alive on the coast long enough to grow new feathers in their new environment.
Genomic analysis identified four Amazonian species in the burial feather assemblage — the scarlet macaw, blue and yellow macaw, red and green macaw and mealy Amazon — all native to rainforest habitat hundreds of kilometers from the Pacific coast.
Transport likely took weeks or even months, as travelers navigated rugged mountain passes and steep plateaus.
"We can now demonstrate with genetic and isotopic evidence that these parrots weren't just traded as feathers — they were transported alive, across dramatic terrain, into coastal ritual contexts," Dr. Olah said.
By analyzing the chemical signatures contained in the feathers, the researchers discovered that the birds' diets shifted to C4 plants, such as maize; and marine protein, showing they were kept alive after crossing the Andes.
"Our analysis reveals the parrots were fed the same nitrogen-enriched diet consumed by their captors — a clear sign of prolonged care after their removal from the rainforest," Dr. Olah said.
Diet clues and trade corridors
Landscape modeling further identified likely trans-Andean corridors and river routes used to transport the birds, revealing sophisticated overland and fluvial exchange networks.
The birds were prized for their vibrant feathers, which held deep cultural value across pre-Hispanic societies and were often used in ritual and high-status burial contexts.
"This discovery challenges long-held assumptions that pre-Inca societies were isolated or fragmented," Dr. Olah said. "Instead, we see evidence of organized exchange, ecological knowledge and logistical planning that connected vastly different environments long before imperial roads formalized these connections."
The research also marks one of the first successful ancient DNA studies of fragile archaeological feathers, opening new avenues for tracking how organic materials moved through ancient trade networks worldwide.
Aside from its deep historical implications, the study also sheds new light on the longstanding cultural significance of parrots in Andean societies — a fascination that continues today and that contributes to ongoing conservation challenges for these iconic species.
This work also involved scientists from Adelaide University and researchers in Peru, Spain, the United States and the United Kingdom.
Reference: George Olah, Ancient DNA and spatial modeling reveal a pre-Inca trans-Andean parrot trade, Nature Communications (2026). DOI: 10.1038/s41467-026-69167-9. www.nature.com/articles/s41467-026-69167-9
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