<P> Beginning in 1968, repeated in 1975, and then conducted at 5 - year intervals, a cooperative pan-continental survey of trumpeter swans was last conducted in 2015 . The survey assesses trumpeter swan abundance and productivity throughout the entire breeding ranges of the three recognized North American populations: the Pacific Coast (PCP), Rocky Mountain (RMP), and Interior (IP) populations (see Figure). From 1968 to 2010 the population has increased from 3,722 to approximately 46,225 birds, in large part due to re-introductions to its historic range . </P> <P> Their breeding habitat is large shallow ponds, undisturbed lakes, pristine wetlands and wide slow rivers, and marshes in northwestern and central North America, with the largest numbers of breeding pairs found in Alaska . They prefer nesting sites with enough space for them to have enough surface water for them to take off, as well as accessible food, shallow, unpolluted water, and little or no human disturbance . Natural populations of these swans migrate to and from the Pacific coast and portions of the United States, flying in V - shaped flocks . Released populations are mostly non-migratory . </P> <P> In the winter, they migrate to the southern tier of Canada, the eastern part of the northwest states in the United States, especially to the Red Rock Lakes area of Montana, the north Puget Sound region of northwest Washington state; they have even been observed as far south as Pagosa Springs, Colorado . Historically, they ranged as far south as Texas and southern California . In addition, there is a specimen in the Museum of Comparative Zoology at Cambridge, which was shot by F.B. Armstrong in 1909 at Matamoros, Tamaulipas, Mexico . Since 1992, trumpeter swans have been found in Arkansas each November--February on Magness Lake outside of Heber Springs . In early 2017, a juvenile trumpeter swan took up residence in the French Broad River in Asheville, North Carolina, marking the first such sighting in that part of the state . </P> <P> Non-migratory trumpeter swans have also been artificially introduced to some areas of Oregon, where they never originally occurred . Because of their natural beauty, they are suitable water fowl to attract bird watchers and other wildlife enthusiasts . Introduction of non-regional species in the Western states, for example through the Oregon Trumpeter Swan Program (OTSP), have also been met with criticism, but generally the perceived attractiveness of natural sites have priority over the original range of any given species . </P>

Where do trumpeter swans go in the winter