Craig C. Downer, noted ecologist/activist and author contends that wild horse overpopulation is a myth and he can prove it scientifically. Downer and other wild horse advocates say the BLM is illegally confiscating land designated for wild horse and burros and leasing it to cattle ranchers. In doing so they are violating the Wild and Free Roaming Horse and Burro Act. Downer and other activists say the round ups will drive the herds to extinction if they continue. Some wild horse advocates including Carol Walker have recently filed a lawsuit against the BLM to prevent further roundups.