Trumpeter swans are year round residents at Turnbull. And so accommodating – there are usually a few in the limited areas open to the public. In April, a possibility would have been tundra swans.

“Differences in pattern of facial skin make lores of Tundra Swan look narrower, shorter, with curved border; most birds fit this description, but there are exceptions. These differences are least obvious in profile view, and most obvious in head-on or top view. Trumpeter has dark skin connecting eyes solidly to bill, while Tundra eyes seem to stand apart from bill.” https://www.sibleyguides.com/2006/02/distinguishing-trumpeter-and-tundra-swans/