I went over to Constitution Gardens to see what ducks were around.  No
Gadwalls or wigeons, alas, but there were
   a pair of Redheads
   a pair of Pied-billed Grebes
   several Caspian Terns.
At the DC Veteran's Memorial, I found
   a Yellow-rumped Warbler
   a loudly singing Brown Thrasher
   two Hermit Thrushes 
   a Ruby-crowned Kinglet
   a family of Blue Jays.
In (and over) the Tidal Basin:
   Caspian Terns
   two Osprey
   a Common Loon in breeding plumage
   a flock of Red-breasted Mergansers (1 male, 8-9 females)
   a Double-crested Cormorant

Everywhere (except in the Tidal basin itself):  robins, grackles, juncos

Jim

Jim Felley
Smithsonian Institution