The U.S. Fish and Wildlife Service's decision to scrap a proposal to list a population of sage grouse found along the Nevada-California border as threatened was arbitrary and made despite findings that some populations of the bird may be wiped out, according to a lawsuit by environmental groups.

The Center for Biological Diversity was among four plaintiffs in the lawsuit filed Wednesday in federal court in San Francisco against the wildlife service and U.S. Department of the Interior.

U.S. Fish and Wildlife spokesman Scott Flaherty said he couldn't comment on pending litigation. The wildlife service has previously said voluntary conservation measures that included protection of key habitat made the threatened species proposal unnecessary.

Environmental groups say the bird is threatened by mining, energy development, livestock grazing, invasive weeds, urbanization and wildfire.

Opponents had argued the listing could affect mining, ranching and other activities in a wide area. The bird's range encompasses parts of Carson City, Lyon, Mineral, Esmeralda and Douglas counties in Nevada, and Alpine, Inyo and Mono counties in California.

The wildlife service had proposed designating over 1.8 million acres as critical habitat for the bird, according to the lawsuit. That proposal was also scrapped.