Mike-
I said that a USFWS wing study told a friend of mine that a duck that had a wing exactly like the one you shot was a hybrid. I do not know if they did anything more than look at the wing to determine that.
So, based on what USFWS said and the dark upper tail coverts and appearance of curls, I said I think your duck might be a hybrid.
If I shot the duck that you would, I would count it as a black duck and anyone that would do differently would have one heck of a time proving his point in court.
Want me to pay for a DNA test for that duck or something? Hybrid or not, I don't care, I'm just sharing what I've heard about blacks b/c I find it interesting.
-D