Thanks to Leah at Bluebird of Friendliness for the tip on the Mystery Duck ID (shown above). I looked at some pictures of Ruddy Ducks, Eiders and Scoters. I found a great picture of a female Common Scoter in 2nd year breeding plummage that looks like a close match. Source: Wildfowl & Wetlands Trust http://www.wwt.org.uk Source: Surfbirds.com
Adventures in New England birdwatching.