Shot today near Petaluma, CA. There are more unique birds than I have brain cells to store. I'm guessing some sort of sparrow and from my books, maybe a Savannah? This is the first time I've seen this one.
This looks more like a Song Sparrow to me with the duller gray-brown plumage. An adult Savannah would have yellow, or a yellowish wash, at or around the lores. They also have a more pinkinsh bill than the Song Sparrow gray one.