California Code, Fish and Game Code - FGC § 2011.5

(a) It is unlawful for a person to remove from a hunting dog any collar, including an electronic or radio transmitting device, without possessing written permission from the dog's owner allowing the removal of the collar.

(b) As used in this section, “hunting dog” means a dog in the field actively engaged in the taking of mammals or birds, or a dog actively being trained for the taking of mammals or birds, that is located in an area where mammals or birds can be taken, at that time and place, in accordance with existing law.

(c) This section does not apply to a law enforcement officer or an animal control officer in the performance of his or her duty, or to a person who is assisting an injured dog.