Pre-Inca culture acquired Amazonian parrots from hundreds of miles away to use their feathers to decorate the dead, new analysis reveals

Around 1,000 years ago, a pre-Inca culture acquired wild parrots from hundreds of miles away in the Amazon rainforest and then kept them captive in what is now coastal Peru, all so people could access the birds' vibrant feathers, which were "prestigious symbols of status," a new study finds.

Researchers found some of these feathers in a 1,000-year-old tomb about 20 years ago. Now, a new analysis reveals the "complete journey of these feathers," including where the birds originated, what they ate, and which routes the live birds were likely carried on before being traded to the Yschma, a pre-Inca society that flourished from about A.D. 1000 to 1470.

While it's long been known that the Inca and other pre-Hispanic cultures traded and valued parrot feathers, the new study is one of the first to reveal that the "Ychsma culture, long before the Inca Empire, participated in a sophisticated trade network that spanned the Andes," the authors wrote in the study.

Researchers first discovered the burial in 2005 after a survey with ground-penetrating radar and a later excavation revealed two large, stone-lined tombs near the Temple of Pachacamac, 20 miles (32 kilometers) south of Lima. In one of the two Yschma tombs, the archaeologists found parrot feather ornaments with vivid colors that had been preserved for centuries.

Now, an international team of researchers has analyzed the feathers' DNA and chemical composition, and concluded that the feathers came from live Amazonian parrots that had been transported, and likely traded, across the mountains, before being kept in captivity on the Peruvian coast. Their new study was published Tuesday (March 10) in the journal Nature Communications.

"Our study proves that centuries before the Inca, societies like the Ychsma, the Chimú, and others were already managing sophisticated, organised, long-distance trade networks," study co-author Izumi Shimada, co-director of the Pachacamac Archaeological Project that originally found the tombs and a professor of anthropology at Southern Illinois University, told Live Science in an email. "They possessed profound ecological knowledge and negotiated trade agreements that connected the Amazon with the coastal deserts, revealing that these states [were] more interconnected."

The discovery shows how much effort these societies invested in what they deemed prestigious objects. At Pachacamac, these feathers were found adorning false heads — cloths filled with reeds and other plants — attached to 34 funerary bundles of deceased individuals who were also decorated with small cinnabar masks, suggesting that the feathers were used in ceremonial activities such as burial rites.

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A view of the Temple of Pachacamac (or Painted Temple) near Lima, Peru, where the feathers were discovered.

One of the 34 funerary bundles with the feather ornaments attached found in one of the tombs.

Another of the funerary bundles with preserved parrot feathers.

Another view into one of the intact tombs found near the Pachacamac temple.

However, it appears that the captive birds weren't living at the temple.

"Our research actually suggests that the large-scale rearing of these captive birds may not have happened at Pachacamac itself (no parrot skeletons, eggshells, or signs of breeding houses were found), but further north maybe in the Chimú Empire, who then traded the harvested feathers south to the Ychsma," study first author George Olah, a research fellow at The Australian National University, told Live Science in an email. The proposed Chimú breeding site is based on the new paper's computer models, he added.

A sacred site

The Pachacamac temple and its oracle served as the heart of the Yschma society, which controlled the valleys around Lima before the Inca conquest around 1470. "Because of the widespread and longstanding reputation of Pachacamac, elites of diverse cultures in ancient Peru sought the privilege of being buried close to the temple," Shimada said. "It is believed that the site contained tens of thousands of burials of elites of different cultures and regions."

After the Spanish conquest in 1533, looters ransacked graves at Pachacamac for centuries, stealing and destroying countless Yschma artifacts. By the time the Pachacamac Archaeological Project began its work in the early 2000s, many researchers believed no intact elite tombs were left by the temple — so the discovery of the two tombs was an "exceptional event," the researchers wrote in the study.

Feather quest

In their investigation, the team looked at the mitochondrial DNA of 25 feathers found in the tombs and determined that the ornaments attached to the funeral bundles came from at least four tropical parrot species: scarlet macaws (Ara macao), red-and-green macaws (Ara chloropterus), blue-and-yellow macaws (Ara ararauna) and mealy Amazons (Amazona farinosa). All of these birds are native to lowland tropical forests east of the Andes, not to the Peruvian coast.

These birds lived hundreds of miles from the Ychsma, which suggests the society traded with others to acquire the birds.

"The fact that they ended up more than 500 kilometres [310 miles] away, on the other side of South America's highest mountain range, proves human intervention," Olah said in a statement. "They do not naturally fly over the Andes."

An analysis of the feathers' isotopes (variations of elements with varying numbers of neutrons in their nuclei) shed light on the birds' diets.

Unlike modern wild parrots' diets, which are rich in fruits and seeds, the ancient feathers from Pachacamac showed diets rich in plants like maize and possibly food linked to coastal agriculture enriched by seabird feces.

"Because they showed a coastal diet, it proves the birds were brought to somewhere along the coast alive and kept in captivity long enough to moult and grow new feathers with the isotopic signature we detected," Olah told Live Science in an email.

The macaw feathers also showed a higher genetic diversity in their DNA, unlike the low diversity expected from a small captive breeding colony. This suggested that local breeding was happening near Pachacamac and birds were being repeatedly sourced from Amazonian populations and moved through trade routes in the mountains.

"While it is tempting to think of them as pets, the archaeological evidence suggests they were maintained primarily for their feathers, which were valuable prestige items used in elite tunics, headdresses, and funerary bundles," Olah said.

Finding the routes across the Andes

To determine how these birds moved across the Andes, the team turned to computational models. They plugged in ancient topography, river systems and ocean conditions, and then ran a "least cost" path analysis to determine which routes would have demanded the least energy from human caravans.

The more efficient routes pointed to two likely corridors: one through northern networks tied to coastal regions where the Chimú Empire was located and another through central Andean passages connecting the coast to eastern lowlands.

"The recommended best paths actually made good sense and also aligned well with historical and archaeological evidence," Olah said.

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