Environmentalists are appealing a judge’s decision that upheld the move to take wolves off the endangered species list.
Monday’s legal filing came on the first day wolf hunting licenses went on sale in Montana.
Wolves were taken off the endangered species list in an unprecedented move by Congress this spring in Montana, Idaho and parts of Utah, Washington and Oregon.
A judge earlier this month was critical of the move, but declared it was constitutional.
The Alliance for the Wild Rockies appealed that decision to the 9th U.S. Circuit Court of Appeals.
The group says it still believes the way Congress made the move was unconstitutional.
Montana hunters are expected to reduce the predator’s Montana population by about 25 percent to 425 wolves in a hunt that starts next month. (AP)