How an Andean Condor poo reveals a 2200-year record of diet and nest site usage

However, in 2014, researchers found a condor nest in Argentina's Nahuel Huapi National Park that provided a wealth of information. According to a report in Proceedings of the Royal Society B, scientists analyzed the poop of Andean condors to uncover a 2,200-year record of their diet and nest site usage. 

Unlike most condor nest sites, this one was sheltered from rain and snow. So, breeding pairs' droppings built up over time, creating a dense, pale mound.

The birds have been using the same nest location for so long, which was "extremely surprising," said paleontologist Matthew Duda of Queen’s University in Kingston, Canada. 

Most species of birds return to the same area to raise young, but rarely the same nest. "If they have been using the same nest and keep coming back over and over and over again, it implies that where these birds are nesting is a super important part of their ecology and behavior," Duda said.

Researchers took a 25-centimeter-deep slice out of the guano pile and used DNA and ratios of specific chemicals in the poop to determine what the condors ate over time. They also analyzed other chemicals, such as sulfur, potassium, and preserved algae, to reveal changing environmental conditions. 

Analyses of the deposit show that the condors changed their diet after European colonization of the Americas. They also practically abandoned the site for millennia, possibly due to centuries of erupting volcanoes. "A material that could easily be ignored or discarded as waste can teach us quite a bit about how populations, communities, and ecosystems respond to environmental change," says Rachel Reid, a paleoecologist at Virginia Tech in Blacksburg who was not involved in the research.

The significance of the research

The change in diet had significant implications for the condors and their environment. "This information is beneficial for land managers and conservationists who are trying to understand what species are doing and how they're interacting with other parts of the ecosystem," Duda said.

Studying Andean condors can be difficult due to their elusive nature, but analyzing their droppings can provide a wealth of information. With this knowledge, researchers can develop better conservation strategies to protect these magnificent birds from extinction.