Many of the birds represented in the Nazca Lines in southern Peru are exotic species, including hermits, pelicans and what appears to be a juvenile parrot, scientists have said. By studying the morphology of 16 of the geoglyphs, researchers say many of the birds depicted should be re-classified—and that having a better understanding of what the species are will provide a better understanding of the lines and what they were created for.

In a study published in the Journal of Archaeological Science: Reports, researchers say the Nazca Lines represent "one of the most attractive ancient mysteries in the world." They were created between the fourth century B.C. to the 10th century A.D. Over 2,500 have been identified, with many different objects represented. Many of these pertain to plants and animals—with birds featuring heavily in the latter category.

Previously, scientists analyzing the lines identified several different species of bird. These include hummingbirds, a duck, a flamingo, a guano bird and a mockingbird. However, these studies generally assigned species based on a few traits.

In the latest research, a multidisciplinary team analyzed the morphology of the Nazca birds and compared them with different species in Peru.

Their findings indicate the geoglyphs represent exotic species of birds found far from where the lines were created. "We revealed several discrepancies between their geoglyphic characteristics and those of the taxonomic groups to which they were attributed by previous research," they wrote.

"In addition, we determined that some of the geoglyphs depicted a number of specific birds, including hermit, pelicans, and what is most likely an immature parrot. Each of these birds is regionally exotic. For instance, hermits and parrots are found in tropical rain forests whereas pelicans live in coastal areas."

These regions, the researchers say, would have been frequented by the people who created the Nazca Lines during foraging trips to the coast.

And the team believes their exoticism is significant: "If exotic/non local birds were not significant for the Nasca people, there are no reason to draw their geoglyph, study author Masaki Eda told Newsweek. "So, their existence should be closely related to the purpose of etching geoglyphs. But the reason is difficult to answer.

"Although there are some animals and plants geoglyphs in the Nazca Pampa, birds are dominant in those geoglyphs. It suggests birds were important for Nasca people."

Why the geoglyphs were created is still a mystery and many explanations exist. These include serving as pre-Columbian roads, for agricultural purposes, as performance areas and ceremonial displays. It has also been suggested that they are expressions of astronomical events.

"To reveal the purpose of the geoglyphs, a precise understanding of what they depict is an essential first step," the researchers wrote.

Eda said he hopes the latest study sparks discussion about whether the birds depicted are the species they assign, adding that more research would be needed to draw any conclusions about their meaning.

"By comparing the birds in the geoglyphs with those drawn on pottery, modeled as vessels, and used in religious activities, we would be able to identify more of the birds depicted in the geoglyphs," the team concludes. "Further, we may be able to detect clues in the other mysteries of the Nasca geoglyphs, such as the reason why birds outnumber other animals and plants, and why the geoglyphs were created."