Federal judge ends Colorado’s plan to kill hundreds of mountain lions Durango, Colorado Currently Mon Project called for removing half the population to study impacts on deer Monday, April 5, 2021 4:50 PM Colorado Parks and Wildlife planned to kill about half the mountain lions in the Upper Arkansas River Basin between Leadville and Salida. National Park Service Federal judge ends Colorado’s plan to kill hundreds of mountain lions Colorado Parks and Wildlife planned to kill about half the mountain lions in the Upper Arkansas River Basin between Leadville and Salida. National Park Service Toggle font size A U.S. District Court judge has ruled that federal dollars cannot be used to fund a Colorado Parks and Wildlife plan to kill hundreds of mountain lions in the Upper Arkansas River Valley as part of a study of the impact of predators on declining mule deer populations.