The photo clearly shows this bird out over the river which should put it into PG County since Belle Haven Park is south of the bridge.

 Tyler Bell


California, Maryland

Subject: White Pelican - Potomac River - Belle Haven 
area
From: Kim <catwisprer AT gmail.com>
Date: Mon, 3 May 
2010 20:38:04 -0400

A White Pelican flew into the Belle Haven Park area this afternoon. It
stayed mostly out in the middle of the river.  I was hoping it would come in
closer- but it was not meant to be.

The link is to a photo  of the White Pelican in flight near Wilson Bridge

http://www.flickr.com/photos/kim/4576844494/