At a distance (several hundred yards initially), I got the impression of the spots on the face of a female-type Surf Scoter, or maybe even Harlequin Duck but the plumage is a little pale overall, and the rear-end of the bird is white. The small bill also doesn't fit for Scoter.

The white spot on the auriculars is a little more pronounced in this shot than it really was. Though not well-illustrated, the darkest winter long-tailed ducks, may show only ill-defined whitish patches about eye and recall female Harlequin Duck.