Scientists studying the world’s largest river turtles, a South American species that grows to a length of nearly a meter, or 3 feet, have found the largest nesting aggregation ever recorded. Using drones to conduct a population survey in the western Brazilian Amazon, researchers recorded a nesting area of the endangered giant South American river turtle (Podocnemis expansa) with roughly 41,000 adult female turtles. The nesting site is on the largest sandbank of the Guaporé River, which forms part of the border between Brazil and Bolivia. “We knew it was an important area, but we didn’t have the full picture of the size,” Camila Ferrara, one of the study co-authors and a turtle specialist at the Wildlife Conservation Society, told Mongabay by phone. Ferrara said the survey was an undercount of the full region’s turtle population since five other smaller nearby beaches were not included, nor were young or male turtles counted. The turtle population in the area has been growing since at least 2014, a win that Ferrara attributes to the work of the Brazilian government’s 40-year-old Amazon River Turtle conservation program in collaboration with local communities. For this study, scientists tested three different methods of counting turtles. Using only on-the-ground counting, they logged around 16,000 turtles. And using only drones, the scientists counted nearly 79,000, with some turtles likely double- or triple-counted as they moved through the sand. The scientists say a third approach they developed produced a more accurate estimate of 41,000. They collected data using both…This article was originally published on Mongabay

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