I noticed an entry for White Ibis in the District today on the iGoogle
widget and contacted Art Drauglis to ask where he saw it.

He replied:

I saw it from the boardwalk approaching the western viewing platform.
Iwas looking in the direction of the river when I saw something poking
around in the mud. It was a juvenile, so it did not stand out as much.
I was able to follow it a little and got a single, distant profile shot of
it by standing on the bench on the platform.
http://www.flickr.com/photos/artdrauglis/4948049813/
It was walking toward the "mouth" of the back pond, so I went down the river
trail to try and get another look, but was
unable to re-locate it.
I was there at low tide today (847) and am not sure I would have seen it
otherwise, since my experience with them is that they like the mud

Art