This morning I saw four juvenile Little Blue Herons and a juvenile 
Yellow-crowned Night-Heron at Hughes Hollow.  Sibley notes that some 
juvenile Little Blue Herons and juvenile Snowy Egrets show "extreme 
similarity" at this time of year.  I believe these are Little Blue 
Herons and not Snowy Egrets because they show uniformly dull greenish 
legs and feet, and because on at least one bird I could see the small, 
dark tips on the outer primaries (on the folded wing) -- which is 
diagnostic for juvenile Little Blue Heron.  Also, one bird was foraging 
in the water with some Great Egrets.  It had the slow, plodding style 
with neck extended that I would associate with LBHE, rather than the 
quicker movements of a Snowy.  I took some photos which can be viewed here:

http://www.flickr.com/photos/35716495@N08/sets/72157624447884113/with/4823974913/

(If the letters "at" appear in the link, you will have to replace these 
with the "at sign" to get the link to work-- "at signs" are sometimes 
auto replaced on this list for various reasons).

Unfortunately, the birds were preening so actively that I did not manage 
to get a single full profile shot!  But you can see the uniformly 
greenish legs and feet, and I believe on some of the photos you can just 
see the dark primary tips.

OTHER BIRDS:  there was a juvenile Yellow-crowned Night-Heron roosting 
with the juvenile Little Blue Herons.  At Riley's Lock, I finally got a 
decent look at the swan that has been hanging around for the past 
several weeks several hundred yards upstream.  It is a Mute Swan.  Up in 
Washington County, I did manage to see the juvenile White Ibis at the 
previously described location around noon.  Thanks to all who provided 
updates on the status of the bird!

Good birding!
Jim Moore
Rockville, Maryland
PLEASE REPORT YOUR BIRD SIGHTINGS to http://ebird.org/