Ala. Code § 36-5-21

It shall be lawful to show by parol that any bond or recognizance was taken by an officer in the discharge of his duty, although such fact ought to appear upon the bond or recognizance or in writing or of record and does not so appear; and, if an officer takes a recognizance in a case where he should have taken a bond, it shall bind the parties in the same manner as if it had been authorized.