By Frits van der Meer from Utrecht, Nederland (barbarijse patrijzen) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
North America. Breeds in Alaska and scattered localities across Canada and the northern USA with the largest area around Alberta. It winters in western British Columbia north to southern Alaska.
Not especially favoured as a species in collections. Like all swans they need plenty of space incorporating large areas of open water as well as grazing land. One was at Hollesley Marshes in Suffolk Dec 2014 - Jan 2015, probably the same bird was at Dovercourt, Essex in March 2016 and another was at Ribchester, Lancs in September 2016.