An adult Slaty-backed Gull was seen feeding with a large concentration of gulls off Pipit Pt at the southeastern corner of Tommy Thompson Park. A dark-mantled gull the same size as surrounding Herring Gulls with a white crescent on tertails, dirty white head with particularly dark area around yellow eye. Yellow bill with red spot near tip. Bubble gum pink feet. Thick white trailing edge to wing, string of pearls at tips of outer primaries, grey underside to primaries. Observed as close as 100 feet for about an hour, both in flight and floating on the lake. Very likely the same bird that has been along the Mississauga waterfront. Tommy Thompson Park is at the south end of Leslie St in Toronto. Good birding, Don Graham