Harris's Sparrow (Zonotrichia querula), spotted in the village of Salmon Creek on 3 January 2015.
This is a rare bird in Sonoma County, especially along the coast. There are only about 18 records listed in the Birds of Sonoma County, and of those, only one is from Bodega Bay (in November 2004). Interestingly, what appears to be a different Harris's Sparrow was documented at the Bird Walk Coastal Access Trail in late November 2014.
Harris's Sparrows breed in the forest-tundra zone of northern Canada and winter in the central Great Plains.
Note the black crown (with scaled patterning), black chin, pink bill, brown cheeks with a dark postocular (behind-the-eye) spot or chevron-shaped marking, and long tail.
Although this photo lacks something for scale, this is large sparrow. At 18-20 cm (~7.5 inches) long, it is noticeably larger than its relatives in the same genus (White-crowned Sparrow, Golden-crowned Sparrow, and White-throated Sparrow).
I introduced the other three Zonotrichias in April 2012 — to compare, you can review that post here.
P.S. Many thanks to Peter for alerting me to the presence of this handsome bird!