An aide to Interior Secretary Sally Jewell said the administration is providing grouse habitat protections on 67 million acres of federal lands, including 12 million acres where strict limits on oil and gas limits will be enforced.

“It's the most complex, the largest land conservation effort in U.S. history,” Jewell adviser Sarah Greenberger said. “This model of science-based, landscape-level conservation is truly the future of conservation.”

Jewell and the governors of Wyoming, Montana, Colorado and Nevada were to make a formal announcement later Tuesday at the Rocky Mountain Arsenal National Wildlife Refuge just north of Denver.

Environmentalists who sued to force Tuesday's decision were certain to challenge it, while industry groups and some Western governors have argued that measures already enacted to prop up the bird's population go too far.

Greater sage grouse once numbered in the millions. Over the last century, the bird lost roughly half its habitat to development, livestock grazing and an invasive grass that's encouraging wildfires in the Great Basin of Nevada and adjoining states. An estimated 200,000 to 500,000 occupy sagebrush habitat spanning the 11 states.

The finding reverses a 2010 determination that the sage grouse were in precipitous decline. Under a federal court settlement, the U.S. Fish and Wildlife Service faced a Sept. 30 deadline to decide the birds' status one way or the other.

Republicans cast the issue as evidence of endangered species laws run amok. Congress last year voted to block Fish and Wildlife from spending money on any proceedings to change the bird's legal status.

The Obama administration has poured hundreds of millions of dollars into conservation measures in hopes of patching together enough sagebrush habitat to ensure the bird's long-term survival. The administration worked with state governments to adopt their own habitat protection plans, which included local restrictions on energy development and setting aside private and public lands as habitat.

The administration also is proposing to withdraw mining claims on 10 million acres considered key grouse habitat.

Under Tuesday's announcement, sales of oil and gas leases that were previously deferred on more than 8 million acres will undergo a 90-day review before a final decision is made.

At the center of the fracas has been Wyoming, home to roughly 40 percent of the bird's population and a hub of fossil fuel development, with huge potential for wind energy and uranium mines.

Efforts to avoid protections in Wyoming have resulted in a significant impact: No drilling may take place near vital sage grouse breeding grounds during nesting season. Oil and gas wells in areas deemed as core habitat for the birds must be clustered together and directionally drilled from well pads.

Other states have adopted similar plans.

The Associated Press