The gray head and nape, the almost white eye-ring without a clear eyebrow and only a faint eyestripe, the line between front and side neck color, and the grayish flank all tend to make me unsure of the OCWA identification.
UPDATE:More info: http://www.surfbirds.com/blog/northcoastdiaries/20778/OCWA%3A+more+than+you+want+to+know....html
At least I can now be sure this is an OCWA!