This video from Ireland is called Juvenile Thayer’s Gull at Enniskillen, Co. Fermanagh – 3rd February 2012. Also in this video: an adult herring gull, and (smaller) black-headed gulls in winter plumage.
Translated from Dutch Birding:
Monday, April 13th, 2015
Last weekend for the first time ever a Thayer’s gull was seen in the Netherlands. Birder Leon Edelaar discovered the bird on the coast of Egmond aan Zee where it sat among other gulls. Birdwatchers from the Netherlands and abroad meanwhile flocked to see the special gull too.
According to photos, this is a young gull.
North America: The western gull may seem common, but because these gulls hybridize frequently with galucous-winged gulls, there are areas of their range where hybrids outnumber the population of pure-blooded birds. At one time the yellow-legged gull was also lumped with the western gull as a single species. Birders who know how to distinguish these gulls, however, will be thrilled to add such a distinctive, elegant bird to their life lists: here.