First bird: I think that the bird is almost certainly not a smithsonianus, and appears to be L. argentatus argenteus, the northwestern European form (though I would not rule out L. a. argentatus) or maybe some hybrid. Comments from those who are intimately familiar with those European forms (as I am not) are desired.
The key marks for me are the tail, the coverts, the tertials, the overall jizz, the fresh scapulars, and the bill, in roughly that order. I have been studying smithsonianus in the East for many years and have never seen one with a tail anywhere even close to this bird's. The tail band here is not even as large as that of a Thayer's Gull. It resembles that of a Ring-billed, as does the bill and primary extension (not that that proves anything necessarily).
The first three photos were taken before November 15, the others in late December.
Second bird: A bit worn looking, with a more robust head and bill. There is no absolute clear view of the entire tail, but from what is shown here it again appears that it could be L. a. argenteus. Unlike the first, this bird does not recall Ring-billed to me. Of course, comments are welcome.
These photos were taken in December of 1998.
There is an extensive discussion of this bird on the responses page (under "Possible argenteus in Connecticut").
For comparison, here's a shot of a juvenile argenteus in Holland in late July 1994. Note the bill and the belly! I took only about six shots of juvenile Herring Gulls on that trip to Holland, so it seems significant that one of them had a bill like this, with so much flesh coloration.
since February 8, 1999