During an extended lunchtime walk, I found the following:

Washington Channel:
Herring, Greater Black-backed and Ring-billed Gulls
A pair of Common Mergansers
Several Red-breasted Mergansers
A group of Lesser Scaup

Tidal Basin:
Herring, Greater Black-backed and Ring-billed Gulls
Lots of Canada Geese
A Ring-necked Duck
The ice still covers about 80% of the basin, and there are a few dead
gizzard shad being fought over, but there were less than a hundred gulls
on the ice.

DC Veteran's Memorial:
Two Fox Sparrows (new for my Mall list!)
A flock of Dark-eyed Juncoes
Robins, Starlings

Constitution Gardens:
Many robins, starlings, grackles and cowbirds
Many Canada Geese
3 male Redheads
An immature Red-tailed Hawk trying to catch a squirrel while a group of
tourists gawked at it (both hawk and squirrel were in the same low tree,
the squirrel trying to stay on the other side from the hawk.  Finally,
with the press of tourists, the hawk finally gave up and flew away).

Jim 

Jim Felley
Smithsonian Institution