March 29 (UPI) -- The recovery of ancient mummified parrots in South America, dating to between 1100 and 1450 AD, suggest trade routes crossed the Atacama Desert, according to a study published Monday in PNAS.
"Feathers are valued across the Americas and we see them in high-status burials," José M. Capriles , said in a press release.
"We don't know how the feathers got there, the routes they took or the network," Capriles, an assistant professor of anthropology at Pennsylvania State University.
Northern Chile's Atacama Desert is the driest desert in the world, and parrots and macaws are not normally found in the region.
However, archaeologists have unearthed the feathers of the exotic birds at human burial sites, as well as the mummified remains of parrots and macaws.
Scientists estimate that the only way parrots and macaws could have ended up in the middle of the Atacama is with the help of humans.
"The fact that live birds made their way across the more-than-10,000-foot-high Andes is amazing," said Capriles. "They had to be transported across huge steppes, cold weather and difficult terrain to the Atacama. And they had to be kept alive."
Capriles is an expert on the ancient trade of coca, shells, metals, feathers and animals throughout what's now Bolivia, Peru and Chile. He also comes from a family of bird experts -- his father is a wildlife manager and his mother is an ornithologist.
When Calogero Santoro, a professor of anthropology at Universidad de Tarapacá, began finding mummified birds, he asked Capriles' mother to help identify the species and their likely origins. Capriles began assisting the research, too.
"Our idea was to say something about these parrots, where they were coming from and what species were represented," he said. "My mother is a co-author on this paper."
The researchers conducted a survey of parrot and macaw remains collected in several of the region's museums. Most of the bird artifacts date to the reign of the Tiwanaku empire, prior to the rise of the Incans.
During this time, between 1100 and 1450 AD, warfare was common. But so was trade.
The survey of bird remains -- involving zooarchaeological analysis, isotopic dietary reconstruction, radiocarbon dating and ancient DNA testing -- showed scarlet macaws and at least five different parrot species were transported more than 300 miles from the eastern Amazon.
The isotopic analysis showed the parrots were eating the same diet as the farmers that acquired them for their prized feathers.
Several of the birds were found mummified with their beaks open and their tongues sticking out.
"We have absolutely no idea why they were mummified like this," said Capriles. "They seem to be eviscerated through their cloaca -- a common excretory and reproductive opening -- which helped to preserve them. Many times, they were wrapped in textiles or bags."
Many of the birds were recovered from a dig site near Pica 8, an oasis community that still serves as a nexus site for trade routes across the desert.
"We know that the birds were living there," said Capriles. "[And] that they were eating the same foods that people were eating enriched with the nitrogen from maize fertilized with marine bird manure."
"Llamas are not the best pack animals, because they aren't that strong. The fact that llama caravans brought macaws and parrots across the Andes and across the desert to this oasis is amazing," Capriles said.