Cal. Fish & Game Code § 4341

Any person legally killing a deer in this state shall have the tag for that deer countersigned by a person employed by the department, a person designated for that purpose by the commission, a notary public, a postmaster, a peace officer, or an officer authorized to administer oaths, before transporting the deer, except to transport the deer to the nearest person authorized to countersign the tag, on the route from where the deer is taken to that person.