I couldn't count the number of ducks that we used to pass up on back when I used to duck hunt all the time in the 80's and early 90's. We always passed on goldeneye, bluebills, mergs, etc. We only shot pintail, teal, gadwall, woodies, mallard, and widgeon. Just what my dad taught us. He had a name (that I can't type here because it would be censored) for all diving ducks.
It's funny because most of the divers eat basically the same things as the puddlers, they just dive to get to their food. It's really just the fish eaters (mergansers) that we should have been passing up.
The other funny part is that my dad refused to eat any duck. My mom would cook up duck for the family and make a separate meal for my dad. I guess we should have been shooting the other ducks as well since he didn't even eat them.