In On the Move, our regular column about migration, we present pairs of distribution maps from eBird that you can use to compare where interesting birds are at different times of year. We featured Trumpeter Swan pictured above, in our December 2016 issue.
Trumpeter Swan is the largest native North American waterfowl and one of the heaviest flying birds in the world. Once abundant and widespread, the species now has a spotty distribution, although many populations seem to be increasing. The swan breeds in central and southern Alaska, in parts of the Yukon and Northwest Territories south through British Columbia and across southern Canada, in parts of the Mountain West, and throughout the Great Lakes region.
When waterways freeze during the nonbreeding season (right map), the swan largely vacates the northernmost reaches of its breeding range and may be seen in almost any area of the continental United States, where it often occurs on large lakes and reservoirs with Tundra Swan and geese. Since Trumpeter and Tundra Swans are similar, birders should note body size, neck length, call, and bill topography as ID aids.
A version of this article appeared in “Birding Briefs” in the December 2016 issue of BirdWatching. Subscribe.
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