Steve Alder of Idaho for Wildlife, the derby's promoter, said the low tally helps prove sport hunting isn't a very effective tool in managing Idaho's wolves.
"This is why the Idaho Department of Fish and Game has implemented trapping and other control methods to better manage wolves," Alder said in a statement. "I can assure you that in the last two days while this derby was taking place, more wolves and wolf pups died in Idaho's back country due to starvation and or cannibalism from other wolves."
Idaho has a hunting season for wolves, as do Montana and Wyoming.
Alder's group offered two separate, $1,000 prizes one for the hunter who killed the biggest wolf, the other for the hunter who bagged the most coyotes.
WildEarth Guardians wanted the Idaho derby scotched on grounds the U.S. Forest Service hadn't issued a special permit, but U.S. District Magistrate Judge Candy Wagahoff Dale last Friday decided no permit was needed.
After losing in court, WildEarth Guardians executive director John Hornung in Santa Fe, N.M., told The Associated Press his group plans to petition the Forest Service for changes he hopes will prevent such events.
"We're going to petition the U.S. Forest Service to update their regulations on these hunts to reflect contemporary science and public attitudes," Hornung said.
While competitive wolf shooting inflamed advocates' passions, derbies targeting other, more-common predators including foxes and coyotes across the West and much of the rest of the country generally proceed without as much public outcry.
For instance, a coyote derby planned for Jan. 11 in Dillon, Mont., will allow hunters to bag the carnivores on U.S. Forest Service and Bureau of Land Management territory, though nobody has challenged whether its organizers have followed the agencies rules.