Found by Cayuga Bird Club on the concrete wall below the control gates at Chippawa, then later behind the Gatehouse just below the two reservoirs opposite Dufferin Islands. I would like to thank Willie D'Anna and Betsy Potter for calling me and Ron Tozer by cell phone to let us know. We spent several hours between 12:30 p.m. and 3:30 p.m. studying its fieldmarks.

Scroll down for four photos showing the mantle shade, which is about the same as Lesser Black-backed Gull and lighter than Great Black-backed Gull, dark streaking coalescing around a pale eye, wide tertial crescent, bright pink legs and in flight it showed the "string of pearls".

Slaty-backed Gull (left) and Great Black-backed Gull on right showing difference in mantle colour. 2 December 2006