As already reported on MDOsprey by Paul O., Gary A. & Gail M. (thanks all),
I observed 2 (actually 3, but I digress) interesting gulls this (Sat., 12/8)
morning along the Anacostia River Park in Washington, D.C.  I arrived at the
park at about 7:30am, it was overcast and there was a light rain.  The tide
was high and falling, and there was a collection of large gulls (mostly
Herring and a few Great Black-backeds) on the river at a spot that usually
becomes a mudflat at low tide (unless the river is really high) and attracts
loafing gulls.  While scanning the gulls sitting on the river, I immediately
found a bird that was Herring Gull in size, but much paler overall and more
gray than brown on the back.  My first thought was 1st cycle Lesser
Black-backed, but as I was observing the bird some field marks didn't fit -
first and foremost, the shape and size was all wrong for Lesser.  It was too
big (again, Herring size), bill was too heavy and it lacked the long,
attenuated tail-end look of a Lesser.  Plus, the bill color, which was
mostly dull yellow with a wide black band towards the tip, said that this
was not a one year old bird, but coming into its 2nd winter.  If it was a
2nd winter Lesser, it should show darker gray feathers in the mantle.  

As I watched the bird and was taking some pictures of it, a car drove by and
flushed all the gulls.  The bird in question flew across the river and
landed on the top of one of the marinas.  When it flew it showed a very
prominent white rump, dark tail, and contrast between the dark outer
primaries and paler inner primaries (which, again, was a vote against
Lesser, among other things).  I got my scope out and as I was watching the
bird and talking to Gary on the phone, a policeman stopped and said that I
couldn't use a scope in the park.  I politely tried to tell him that other
law enforcement officers have said that the "no tripod" rule only applied to
photography, and I was only observing the bird.  He said that he didn't know
optics well enough to know the difference between a camera and a scope,
while also admitting that he didn't know the full language of the law.  He
then said that he was going to go back to the station and check the book,
and if he found that he was right and I was wrong, he would take appropriate
action.  Not wanting to push it too far (as I didn't know the full language
of the law either), I took the scope off the tripod and watched the bird
with the scope resting on the roof of my car.  Of course just as I got on
the bird it walk down the slope of the roof to a point where it was out of
sight.

At that time a new flock of gulls landed in the ball fields, and I had found
another interesting gull - sort of Iceland/Thayer's like.  But I didn't see
it well enough to by able to ID it before it and all the other gulls took
off.  So I looked back at the marina and was surprised to find that the
first bird was back in sight.  I took fairly extensive notes and some more
bad pictures (trying to digiscope as the scope rested on my car roof - not
an easy thing to do).  I was hoping Gary and crew would arrive quickly,
before the bird was out of sight again.  They finally arrived, and as Gary
mentioned, he only got a brief look at the bird before it took off and flew
up river, out of sight forever.  

In any case, I've posted these bad pictures on the web at:
http://picasaweb.google.com/cheep.paul/InterestingGull11207.  Bill Hubick I
am not!  Here are some features to note on the various photos:
-	the tertials are very dark gray, almost the same color as the
primaries and with a wide white tip
-	the scapulars are mixed (some old feathers, some new).  Note that
some are almost as dark gray as the tertials, and with white tips
-	the mantle is a light to medium gray (very hard to discern in the
photos), slightly darker than the nearby Herrings (I don't think this is
visible in the photos).  It also seems to be retaining a fair number of
older feathers in the mantle (ie, the new, all gray feathers are few)
-	the wing coverts are patterned in light brown and white (it was
difficult to discern actual pattern, and they look darker in the photos of
the bird on the marina than they were in real life)
-	the legs are light pink, not as bright as the Herrings
-	the lower nape has fairly wide brown streaks, which quickly fade to
fine streaking on the crown
-	the eyes are dark with dark feathers around them (suggesting the
"black eye" look of a Lesser in winter)

As mentioned above, the light levels were really low when I took the photos,
making everything look darker than in real life.

Many of these features are consistent with Yellow-legged Gull, but I'd like
to take some time to review the literature before trying to give it a name.
Other birds that seem close but are equally rare include European Herring,
Vega, and Western, or of course a hybrid.  But again, this is based on
little literature review so far.

Also, a few photos of the other bird that was found by Gary and now called a
runt Ring-billed are posted at:
http://picasaweb.google.com/cheep.paul/InterestingGull31207.  I'm posting
these, in part, to show that I am capable of digiscoping, sometimes.

I welcome any comments (except those pertaining to the quality of my
photos).  I hope to go out Sunday morning to look for the bird again.

Good birding,
Paul Pisano
Arlington, VA