I went back with Ted Murin and met up with Jim Mead and David Hoag at 
the Sandbar causeway.  We relocated the bird after about 30 minutes and 
were able to watch it, albeit from ~500 yards, for about 20 min.  It is 
a third year bird, so it has a streaky head, limited white in the outer 
primaries, some brown in the coverts, and some black in the tail.  
Although it would be nice to get some better looks at this bird, it 
appears to be a Slaty-backed Gull.

Pertinent field marks:
Dark gray mantle and wings, grading into black outer primaries
Pink legs, visible from quite a distance
Size similar to a Herring Gull, perhaps slightly larger; smaller than a 
Great Black-backed Gull
Head and hind neck heavily streaked
Bill not as bulbous as a Western Gull
The white trailing edge on the tertials, secondaries, and inner 
primaries was noticeable, although not as prominent as portrayed in some 
drawings.  We could see this feature while the bird was standing on the 
ice as well as when it was flying.

At about 3:45 the bird flew north, but landed on the ice, barely within 
sight.  With dying fish in the area, it would seem likely that the bird 
will stick around for a while.

Good luck if you go,
Allan


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Allan M. Strong
University of Vermont
The Rubenstein School of Environment and Natural Resources
007 Hills Building
Burlington, VT 05405
802-656-2910
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