Give Invasive Species a Job

Updated at 1:40 p.m. on August 19, 2023

In 2014, William Simpson II was in his cabin in the Soda Mountain Wilderness area, near the California-Oregon border, when he heard a mountain lion screaming in the night. He got a flashlight and went outside. “I saw these big blue eyeballs seven feet off the ground,” he told me. Only once his eyes adjusted did he realize three black stallions were out there, staring right at him.

Simpson had spent time with domestic horses—he had grown up on a ranch, before studying science and working in forest management and logging—but he had not known that wild horses spent their nights avoiding predators. He began closely observing the horses. Now, after more than 15,000 hours studying them, he has become an expert in wild horses, which many people consider little more