Found my bird guide finally. It was practically under my nose. Looking at the ducks I realized that all my black and white ducks were not common merganser.
I posted a picture of this duck last year but this is a clearer shot. I took the picture of these ducks on the 12th of April last year. So I am putting a reminder in my calendar to go looking around the same days to see if I can get and even better picture next year.