Age: The pointed primary tips, neatly patterned wing coverts and tertials, and overall appearance suggest a 1st cycle gull. The warm mottling on the breast and underparts are also typical of a 1st cycle.
Identification: This appears to be a member of the white-headed gulls (as opposed to the smaller tern-like or hooded species). The bill is strikingly petite and "short". At first glance it would seem this is an Iceland Gull due to the pale primary edges, icy-gray post-juvenile scapulars and overall frosty appearance to the upperparts. But we'd be pressed to find a 1st cycle Iceland with this much solid gray on the back in January. This is a 1st cycle Short-billed Gull (L brachyrhynchus), formerly known as Mew Gull in North America. Individuals with this plumage aspect are sometimes described as "mini Thayer's", and overall the plumage patterns are similar. In the field -- which can't be appreciated here -- the diminutive size of this species would be quite obvious.