Cal. Fish & Game Code § 4341

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