Bob, not sure but it reminds me of an first year king eider hen.
Tim, " dwarf" is offensive. I think they would rather be refered to as ". Little birds".....
I will go sit in the non-PC corner.
On some hen Kings there is a more noticeable light ring around the eyes. Maybe in younger ones it is even more apparent. Like this one Click here.
I would expect even a young King to be bigger but maybe they grow into that size slowly. Like I've said I've only seen adults and they are larger ducks. It's almost a process of elimination that it's about all it could be. I don't think it is a hybrid eider but it could be... but I doubt it.... but it could be.
Tim