This adult gull was at Horseshoe Lake in Loveland, Larimer County, Colorado on the morning of 3 Dec 2014. Photos are lousy because I was holding my 70 mm lens against the 20x eyepiece of my Kowa spotting scope, and shooting through 4 dirty lenses in poor light (overcast) without a functional autofocus. Nonetheless, with a little imagination :-), the images do show a large gull the size of American Herring Gull, with a mostly white head (streaks limited to lower nape, and a smudge around the eye), a yellow bill with a small red gonys, a gray mantle almost as dark as nearby California Gulls, a thick white tertial crescent and strong pink legs. I believe that these are characteristics of Larus vegae vegae (or L. argentatus vegae), which is the western (Alaskan) race of the Siberian Herring Gull, a taxon not yet accepted on the official state bird list in Colorado.
