The bird in the photo at http://www.pbase.com/rickbowes/image/150775209, also a loner, was present in the same spot on June 5. It seems likely that this photo taken today (6/19)is the same bird. While this photo is marginal (zoomed to 400mm & fully enlarged)my observations via the scope confirm the SBDO. The location is in the panne-like area opposite Plum Hills in the Gurnet marsh.