Common Eider

Early on while exploring Spectacle Island in Boston Harbor, I noticed what looked like a large duck or small goose sitting on a rock just off shore. At this point on the island, the trail was at the top of a sea wall made up of large boulders, so I couldn't get very close (though I did eventually crawl down the rocks a bit). Due to the distance and the fog, it was hard to see the birds features let alone identify it.
One feature that was vaguely apparent was a rather large, pale stripe across its eye brow. The last time I saw duck with a white stripe like that was a Garganey in Switzerland as seen below.

Eventually, another duck just like the first swam in from the fog and slowly made its way towards the rock.

I really didn't know what species I had seen. The next day while at the airport, I browsed through my field guide and through Cornell's All About Birds online guide looking for a duck or goose with an eye brow like these birds, but the only thing that came close was a Garganey. A few things bothered me however; its bill seemed too heavy and its nasal openings too far down its bill. It was also lacking the loose feathers on its back that Garganey have, though I read they loose those in the winter. The other obvious problem is that a Garganey in North America would be a very rare sighting.
On the off chance that I had actually seen a couple of Garganey in Boston I decided to upload a picture to my Flickr account and posted a link to MASSBIRD, Massachusetts' version of OBOL. I also CC'ed it to OBOL. It didn't take long before I got replies letting me know that these are actually Common Eiders which have become fairly common in the harbor.
Those that seemed most certain claimed they are 1st winter males, though some think they are adults in basic plumage. Regardless, there are not very many pictures on the web that I can find that show a Common Eider with such a prominent white eye brow as these birds. However, now that I know what they are, I can see the unusual Eider bill structure that I had wondered about.
New life bird number 3 from Boston!