Hi,
Today (21 April) I saw an adult Thayer's Iceland Gull in Brantford on the Grand River at Scarfe Ave. When I first saw it I thought it was a very dark Kumlien's Gull but on looking at it further it seemed more attributable to the Thayer's subspecies, looking
much like they do on the west coast of North America. Thayer's Gull often has dark eyes and although the iris on this bird was not "dark", it was not light either.
According to the Birds of Hamilton this is a late date for this subspecies. The only later spring departure date was a 1st-summer bird at the foot of Brant St on 5 May 1999.
Bill