Since 2010, the Sage Grouse Initiative has enrolled 1,300+ ranchers to conserve over 5 million acres of sagebrush country, benefiting 350 species

One year ago today, the U.S. Fish and Wildlife Service announced that the greater sage-grouse did not warrant protection under the Endangered Species Act. This historic decision was due in part to unprecedented voluntary partnerships like the USDA's Sage Grouse Initiative (SGI) that are working to conserve America’s vast sagebrush country. To mark the anniversary, SGI released an online report tracking sagebrush conservation outcomes across 11 western states over the past year. The results show that conservation efforts for the sage grouse also benefit 350 other species that depend on healthy sagebrush habitat -- including people."We're in this for the long haul," says SGI coordinator Thad Heater. "We look forward to maintaining momentum through our $211 million sage grouse investment strategy, dubbed SGI 2.0, that will protect an estimated 8 million acres by 2018."  Heater also notes that the collaborative conservation model launched with SGI is spreading. Private landowners across the nation are now putting in place practices that benefit all sorts of at-risk species as well as agricultural operations through NRCS’ Working Lands for Wildlife. Conservation initiatives are underway for turtles, fish, and rabbits, as well as sage grouse.Since 2010, SGI has worked with dozens of partners and 1,300+ ranchers to conserve over 5 million acres of prime wildlife habitat and agricultural rangeland...more

With respect specifically to the sage grouse, its a real stretch to call this "voluntary". Its the threat of a listing that has forced most landowners to participate.
 
If you threaten somebody and they respond, was their response voluntary? Or was their response caused by the threat.