Photos of a distinctly dark-mantled adult Lesser Black-backed Gull, South Monomoy Island, MA, 18 Sep 2010. This bird appeared consistently darker than the several other Lesser Black-backed Gulls present, and was at least showing the characteristics of the subspecies intermedius, which is rare in North America. It also appeared smaller and slimmer than the other Lesser Black-backs present, and the wingtips seemed to be raised higher when swimming. Comments welcome.