Largest known turtle nest documented in drone study
In the western Brazilian Amazon, scientists have documented the world’s largest known nesting aggregation of the endangered giant South American river turtle (Podocnemis expansa), reports Shanna Hanbury. Using drones and ground counts on a sandbank of the Guaporé River, which marks the border with Bolivia, researchers estimated around 41,000 adult females gathering to lay their eggs.
“We knew it was an important area, but we didn’t have the full picture of the size,” said Camila Ferrara of WCS.
The population has grown in part thanks to Brazil’s four-decade conservation program, carried out with local communities. Yet threats persist. Illegal traders continue to seize turtles by the hundreds, while habitat loss looms. Turtle meat, once sustainably harvested, has long been a staple in Amazonian diets—ranking second only to fish in archaeological records from 7,000 years ago—but today’s demand far outpaces historical levels.
To count the nesting turtles, the scientists combined ground surveys, drone imagery and mathematical models to correct for errors such as double counting or missed individuals. The method produced a more credible estimate than either approach alone and offers a stronger tool for monitoring mass nesting events. By improving accuracy, it allows conservationists to distinguish genuine declines from statistical noise—vital knowledge in the struggle to protect one of the Amazon’s most threatened species.