Parrots and macaws are not native to the Atacama, which is the driest desert in the world, but feathers and mummified birds have been found at archaeological sites in the region, according to a news release from Penn State University, published Monday.Many parrots were mummified after death, some with their mouths open and their tongues sticking out, and others with their wings spread as if they were flying.This is a mummified scarlet macaw.”It’s difficult to interpret,” study co-author José M. Capriles, assistant professor of anthropology at Penn State, told CNN, but the practice may be part of a ritual linked to the birds’ ability to mimic human speech.Researchers visited museums throughout northern Chile for almost three years to study parrot and macaw remains found in the region. The scientists used zooarchaeological analysis, isotopic dietary reconstruction, radiocarbon dating and ancient DNA testing to build a picture of the birds’ lives.Read MoreShown is a scarlet macaw from the Bolivian Amazon.The team found that the birds were brought to the Atacama from the Amazon, around 300 miles away, between 1100 and 1450 CE.That time period saw a lot of commerce, with an increasing number of llama caravans moving between different parts of the Andes mountain range, Capriles told CNN.”The fact that live birds made their way across the more-than-10,000-foot-high Andes is amazing,” Capriles said in a news statement. “They had to be transported across huge steppes, cold weather and difficult terrain to the Atacama. And they had to be kept alive.”Researchers finally solve mystery of 'alien' skeletonThe birds’ arrival predated the Inca Empire and the Spanish colonization of the region, which brought horses to South America for the first time. “Llamas are not the best pack animals, because they aren’t that strong,” Capriles said in the news release. “The fact that llama caravans brought macaws and parrots across the Andes and across the desert to this oasis is amazing.”Once the birds arrived in the Atacama, they would have been kept as pets but also regularly plucked for their feathers, which were used in headdresses denoting wealth and power, Capriles told CNN.The birds were fed the same food as the people who kept them, but their relationship with humans was complicated, he said.Surprise! The world's oldest mummies are not in Egypt“What we consider acceptable interactions with animals under our care was very different back then,” Capriles said. “Some of these birds did not live a happy life. They were kept to produce feathers and their feathers were plucked out as soon as they grew in.”Many questions remain about the birds and the way they were used, and Capriles plans to continue his research in the region.The paper was published in the journal Proceedings of the National Academy of Sciences.