It does have a wait list, but unless you are really high up on it don't count on it too much. Most people who are offered a spot at Davis end up taking it.
I'm not sure how accurate this is, but I heard through the grapevine of a student being told she was #2 on the waitlist...normally we'd all be thrilled with that right? I heard she didn't get in. Do you really think it's possible that no one turns down UCD?