This adult Iceland Gull visited Boyd Lake in Loveland briefly on 1 March 2008, seen by myself, Andrew Spencer, Paul Oppler, Connie and Al Kogler, and Warner and Ruth Reeser.
Note the pale gray spots on the tips of the primaries, a field mark consistent for the kumlieni subspecies ("Kumlien's Gull") and the yellow iris. Thayer's Gull has a dark iris, and much more extensive gray on the wingtips.
This may be the first adult Iceland Gull recorded in Colorado. There have been a few other Iceland Gull sightings in Colorado in 2008.