A Lesson for Ravens: Don’t Eat the Tortoises

Tim Shields didn’t see any young tortoises himself. For the most part, the only sign of them was their shells, desiccated and punctured, scattered around the landscape and piled under the occasional Joshua tree. He was working on a long-term monitoring project in the Mojave and Sonoran Deserts, where over the past few decades juvenile tortoises had all but disappeared from the study areas. This particular year, the scientists and volunteers spotted a single live juvenile tortoise—in the beak of a raven, flailing its legs as it was carried away.

That was eight years ago, and it marked a turning point for Shields, he told me, sitting in his kitchen in Joshua Tree, California. While desert tortoises face a range of threats, for juveniles whose shells are still soft, raven predation is perhaps the biggest concern. Shields knew that past efforts to control the canny birds by shooting or poisoning them had faced legal challenges