I had hoped for a good shot at the upperwing or tail, but as usual, didn't happen. The white uppertail area with broad black band is evident. And even though the bird is fluffed-up, the long wing extension past the tail is very apparent. These birds aren't significalty bigger than a Ring-bill, and look small compared to most Herring Gulls.

The other Lesser Black-back was very similar, but slightly lighter background on the underparts, and a little more obvious covert bar at rest.

Also in the area, and a bird that it took me about 3 hours to find, was the 1st-winter Thayer's Gull. It briefly came into view when a couple of Ring-bills started fighting, but then the gap closed right back and I never saw it again.