Most of the gulls roosting along the Anacostia (at least, earlier this week) are Ring-billed Gulls. Amongst these smallish gulls, a Greater Black-backed Gull (which was also present in low numbers this week at points along the river) would stand out. The are our largest gull and quite impressive, and interestingly, one of the more common species in Washington DC. There were also a fair number of Herring Gulls along the Anacostia, but unlike in November, no Laughing Gulls. However the big roosting flocks are usually 80% or more Ring-billed Gulls.

Your bird was almost certainly a GBB Gull.

Winter is an excellent time to go to areas where gulls congregate and look for rarer species, such as Lesser Black-backed Gull and even a white-winged gull such as Iceland (which have already been reported from Northeast MD this month). 

Gail Mackiernan
Colesville, MD

-------------- Original message ----------------------
From: Cathryn Reid <>
> Today as I came over the Frederick Douglas Bridge (Suitland Parkway/S Capital 
> St) there were a large number of gulls congregated on a rooftop to the left on 
> the DC side - way more than usual. Among them was one VERY large gull type, uh, 
> gull(?) -actually I think there were two of them but.. the congregation of gulls 
> looked to be regular issue Herring Gulls ( I think they are Herrings) and this 
> other 'gull' was very, very much larger than the others and very black and white 
><snip>