If you look at field guides from 5 or 10 yrs ago, the range map doesn't go anywhere near northern California - they are southern birds that like to nest in palms. But in inland Mendocino county folks have been planting fan palms (the only native palm in the state) and the orioles have been steadily following them. Well, this spring/summer our neighbor's fan palm hosted a nesting pair. Unfortunately a fledgling tried to fly through a plate glass window and now rests in peace under a big tree....but at least 1 or 2 others are out there with their parents.
So don't' believe the books...or, if your field guide is more than 5 yrs old, you may want to spring for a new one! (I just did, and per longstanding tradition, passed the old one along to a newbie)