I just saw the adult Slaty-backed Gull at the Westminster landfill in south London. It was in a field with the gulls west of the intersection of Manning Drive and White Oak Drive. Be careful out there, roads are slippery and there are whiteout conditions. Good birding, Quinten Wiegersma London, Ont https://birdsbugsbotany.blogspot.ca/ qwiegersma@hotmail.com