You don't need a license, and the only restrictions are on access and travel on the land. Horn hunters, like other outdoor recreationists, must secure permission to cross or look for antlers on private land, and they must abide by transportation restrictions on federal and state public lands. Horn hunting typically starts in early spring. Deer, elk and moose shed their antlers over the winter, following the mating seasons. Pronghorn is the only species with horns to annually shed its horn sheath. Just after mating season, the pronghorn sheds its horns and only the permanent core remains. The horns of bighorn sheep that have died of natural causes also may be recovered but may not be sold, bartered or transferred to another person without a permit from Fish and Game. Bighorn sheep horns must be permanently marked with a metal pin at an Idaho Fish and Game regional office within 30 days of recovery. But horn hunters are asked to avoid disturbing animals during winter while they are conserving their resources trying to make it through to spring.