BILLINGS, Mont. (AP) — Wildlife advocates have sued the federal government in a bid to force officials to do more to conserve Canada lynx, a snow-loving cat that has struggled to survive in parts of the U.S. West. Attorneys for Friends of the Wild Swan, Rocky Mountain Wild and other groups filed the legal complaint Tuesday in U.S. District Court in Montana. The move comes almost three years after the Fish and Wildlife Service said it planned to strip lynx in the U.S. of their threatened species status. Some scientists and wildlife advocates have warned that climate change could reduce lynx habitat and the availability of its primary food source — snowshoe hares.