This is M.m.samuels, or “Samuels” Song Sparrow. It is resident to a narrow tidal marsh habitat in San Pablo Bay, the northern most arm of the San Francisco Bay. It is one of three subspecies inhabiting the salt marsh. Most likely to be confused with the “Alameda” Song Sparrow of the south SF Bay, but they are never found together. The “Alameda” Song Sparrow shows subtle yellow wash on the belly and olive tones to the nape and back. By contrast, “Samuels” is marginally tanner and does not have a buffy malar. Between these two populations resides the “Suisun” Song Sparrow which is visually quite different. I’ve completed illustrations for all three, but plan on revisiting them to improve the drawings.