Hi Walter,
I saw the bird upriver in St. Etienne-Brule park, near Old Mill. I googled pictures of the immature King Eider and it does look like the bird I saw. The only thing that's making me doubt it is the bill - the bird I saw didn't have the same bill as an immature Eider. It looked like a Mallard's bill but slightly more pointed, if that makes sense?
I'm not familiar with King Eiders at all so could it still be an immature bird with an undeveloped bill?
Neev