I found a Vesper Sparrow this morning while I was walking around corn fields at Aquasco Farm, a Patuxent River Park in southeast Prince George's County. The bird was flocking with a few Savannah Sparrows in the field and road next to the barn.

http://www.flickr.com/photos/35144142@N04/4491101322/

Other highlights from Aquaso Farm, Merkle, and Selby's Landing respectively were my FOY Gnatcatcher, Purple Martin, and Yellow-throated Warbler. 

Also, John Hubbell found a juvenile Little Blue Heron at Selby's Landing on the PG side of the river. Though by the time I saw it, it had moved to the mudflats on the Anne Arundel side. The river is only about 100 yards wide at this point, so it only takes a 50 yard flight for the bird to go from a pretty decent bird to a trash bird, thanks mostly to Swan Creek. Of course that's from a listing mindset; it's still a cool bird to see regardless of county lines.

Robert Ostrowski
Crofton, MD