A sizeable group of birders turned out to Rock Creek Park today.  I can only list what I saw or heard others saw.
In the AM Maintenance Yard.  Just listing the migrants - 
 
Flock of Rose Breasted Grosbeaks
Common Yellowthroat - several
2 Black and White Warblers
2 Redstart Warbler
Magnolia Warbler
Northern Parula Warbler
Blackthroated Blue Warbler
2 Nashville Warblers
2 Ruby Throated Hummingbirds
Eastern Phoebe
Traills Flycatcher
Chimney Swifts
Catbirds - oodles
 
Evening Birds - 6:30 - 7:30 p.m.
Eastern Phoebe
Rose Breasted Grosbeaks
Chimney Swifts
14 Nighthawks!  They fed overhead for a while and headed to the SW
 
Denise Ryan
Washington, DC