Thanks to Andy and Chrissy for giving me a call on the two scoters at Riverlands Migratory Bird Sanctuary in St. Charles Co. I headed toward Ellis Bay from the wave break jetty and two Snow Buntings at the Long Branch Lake Marina about 12:05 pm and arrived at the scoters's site about 2:50 pm and joined the scoper group looking at the scoter ducks.
Here is the checklist with Andy Reago's photos of the scoters.
I think both scoters are immature males which helps explain the not so clean cut cheek patch on the first winter male Black Scoter. It would be good to get an upclose clear photo of the bill so the cere and head color patterns can be seen more clearly. Look at the chart of the common and black scoters on page 201 of the article at the URL below. It's in German but has captions in English. Common Scoter is C. nigra and nests in the artic regions of Eurasia and Black Scoter is C. americana and nests in the arctic regions of Alaska and Canada.
All comments welcome.