Hooded Merganser are a fairly common winter visitor to Utah. They are not widespread but usually quite local, favoring the same ponds and lakes each year. Washington County sees a fairly good number of these birds each winter, with one of the best locations to view being Stratton Pond in Hurricane:

Hooded Merganser. Copyright Tim Avery

Besides Stratton Pond there are often "hoodies" at Tonaquint Park and any number of golf Courses around St. George. A couple winters ago the Entrada Golf Course on the way into Snow Canyon was a great spot to take pictures:

Hooded Merganser Photos

In northern Utah, Kaysville Ponds is usually a pretty good bet for seeing this winter specialty.