Black American Duck? Common Male Merganser? ?

As I was driving north today, I drove down route 113 in Holderness looking for the Shovelers at Carns Cove. I didn't find the cove, and didn't see the shovelers but saw the following water fowl:
I have looked online to try and identify these waterfowl, but cannot.  If you have any ideas, please comment below.
Thank you                         Is this an American Black Duck?

On the way home, I stopped at this large man made pond in Wentworth and saw the following:  I know one is a mallard.  Could the one with the dark head and mostly white body be a common male merganser?  I am not sure about the duck with the mostly white or all white head is, behind the mallard.  Could it be a hooded merganser?    Not sure from this distance.  I couldn't get close enough to get a better shot.

Below:  2  more pictures of the same black and white fowl, side and back view.

This is as large as I dared to enlarge these photos without distorting the picture too much.

Could these 2 pictures be of a common male merganser?