the photo breaks up when enlarged, so it's really hard to tell- I have no solid ideas for a larger-than-robin, yellow-billed, long-rounded-tailed, black bird- good luck!
brewers, grackles have black bills- starlings were near, you said no... brown jays, which have yellow bills as juveniles, don't really look black, don't live in Calif, and don't look like your bird-
I just got back from Aptos- Sand Dollar Beach...
please post again if you get it figured out!
online armchair birding...