Tattooing usually requires anesthesia, and therefore, is a little more expensive. She may think a microchip is the cat's pajamas. This form of identification is injected under her skin in the shoulder region. Every veterinary office in Yolo County is equipped with a microchip scanner to identify lost pets. The SPCA and Animal Control shelter, as well as the UCD Veterinary Medical Teaching Hospital, also have scanners.
Details are important.
A list of all the veterinary hospitals is available in the yellow pages of your phone book. The SPCA can be a valuable ally on your search since they station staff at the pet stores in town as well as at Animal Control in Woodland. As a fellow finder of lost pets, I can not emphasize this enough. The shelter is as busy as Times Square sometimes and the person at the front desk often doesn't have a chance to see every animal that comes through. File lost ads with the local newspapers, and, if you live in Davis, this means the California Aggie too.