Returning from a couple of hours birding on Duxbury Beach, I stopped to check Town Pier (Mattakeeset Court). Occasionally one may get close looks at waterfowl, loons, grebes and once in a long, long while an alcid. At high tide they can drift in very close to the parking lot. This bird was in company of 2 juvenile Common Eiders viewable from town pier. A King Eider is very uncommon in upper Duxbury Bay though almost every year one or two will show up off Duxbury Beach or off Gurnet point. This bird was mostly dozing and drifting between 2:00-2:15pm (high tide was 1:41pm @ 11.0 ft). Waters were quiet in pier area though choppy out in Bay.
Because waters become so shallow at low tide (0.6 ft on 30th) as tides ebb, birds usually leave the immediate pier area, and transients usually don't return. I've not seen it again.