This is a House Wren (Troglodytes aedon), photographed on Bodega Head on 5 October 2013. The genus, Troglodytes, is sometimes translated as "cave-dweller." The "cave" portion of the name likely refers to either the nest cavity or the dense vegetation or dark crevices that the birds favor. [The species name, aedon, means "nightingale" and is a tribute to their complex song.]
Although more common elsewhere in Sonoma County, House Wrens are considered rare migrants and winter residents on Bodega Head.