Federal officials are proposing to substantially expand hunting in Utah’s Bear River Migratory Bird Refuge as part of a wider effort to boost hunter access to the nation’s wildlife preserves and other public lands.

Some conservation groups are skeptical of the plan, outlined in a draft environmental assessment released last week by the U.S. Fish and Wildlife Service.

The agency intends to invite hunting into another 13,500 acres, bringing the amount of the refuge available for that use to the legal maximum of 40 percent.

Federal law requires at least 60 percent of the 77,00-acre refuge, located on the Great Salt Lake’s northeast shore outside Brigham City, remain an “inviolate sanctuary for migratory birds,” closed to hunting and other uses that would disturb wildlife. Bear River was established in 1928 to provide sanctuary for millions of water and shorebirds that rely on the saline lake and its estuaries as a critical stopover on their migrations.

“Refuges are meant to provide refuge for migratory birds that are looking for a place to rest after these long journeys,” Allison Jones, executive director of the Wild Utah Project (WUP), said. “Is it prudent to max out the amount of acreage all at once at all these refuges?”

The group intends to fully participate in the environmental review, which had been kept under wraps until last week.

“We look forward to collaborating with the Fish and Wildlife Service to help bring conservation biology principals from the ecological literature regarding best practices for maintaining and improving wetland refuges habitat and associated native species in perpetuity,” said WUP biologist Mary Pendergast.

Since taking office last year, Interior Secretary Ryan Zinke has championed the idea of increasing hunting and fishing opportunities on public lands, especially wildlife refuges. Last year, he issued a secretarial order directing various federal land-management agencies to produce plans for expanding access.

The Fish and Wildlife Service responded last month with a proposal to open more than 248,000 acres on 30 refuges across the nation, including Oregon’s Cold Springs and Upper Klamath refuges.

“As stewards of our public lands, Interior is committed to opening access wherever possible for hunting and fishing so that more families have the opportunity to pass down this American heritage,” Zinke said in news release. “These 30 refuges will provide incredible opportunities for American sportsmen and women across the country to access the land and connect with wildlife.”

The public may submit comments on the Bear River proposal through July 8.

Through the years, this refuge has expanded, covering more and more wetlands where the Bear River meets the lake, while the marshes available for hunting have not grown, according to Fish and Wildlife. Hunters now have access to 22 percent of the refuge, mostly along its eastern fringe near Perry and on its west side surrounding South Bay.

The proposal released last week offers three alternatives for adding units adjacent to the ones already open. “Core rest areas” would remain off-limits to hunting. Species to hunt are duck, geese, coot, tundra swan, as well as one upland game bird, ring-necked pheasant.

Hunters would be able to access these areas by airboat.