Upon impounding an animal, the Administrator shall make a prompt and reasonable effort to locate and notify the animal's owner. A notice under this Division may be served either by delivering it to the last known owner, or by leaving it at the person's usual or last known residence, or at the address given on the animal's collar, or obtained by means of a pet license, microchip or tattoo, forwarding it by mail to that person at his usual or last known residence or the address given on the collar. When convenient, the notice may be given by telephone to the owner.