Are these ring neck ducks?

I believe that these are Lesser Scaups.
Ring-Necks have a white place in-between the beak and head, and a white tip close the the ends of their beaks, they do resemble though.
Ring-Necked Duck

Randy

After looking at them again, I think they are Ring-Necked Ducks.
The picture's hard to see really, but it does look like you did capture some after all, sorry about being wrong.
Lesser Scaup's have a lighter colored back, these don't, for one thing...

Concur - appear to be ringers.

Ringnecks.