I spent most of the day, off and on, at Conowingo Dam. The Slaty-backed Gull was seen well from before 3 PM until at least 4 PM when I left. It was on one of the front-rank rocks about 100 yards downriver from the end of the large wall extending out from the main dam. It could be viewed both from the catwalk or from the shore at the end of the parking area. There were probably at least 100 observers. The other specialties that I'm aware of were a first-winter and a second-winter Thayers Gull, a second-winter Iceland Gull, and several Lesser Black Backs. Steve Sanford Randallstown MD