You could not be more wrong. Blacks and mallards are the exception in hybrids, not the rule. If you think Spallards or Brewers are out there breeding you’re drunk. Mule ducks. Sterile.
To this day I can't hardly tell the difference in a bluewing and cini hen, but that tear drop on the Cini Drake looks an awful lot like a green wing teal to me. That is an awesome bird.
I think the Cin teal hen has a bigger more shuv like bill than a bluey. Some agree some disagree with this...
I guess we will agree to disagree, theres pictures of F2 and F3 mallard x pintails and others if you look. Just because they arent common and we dont see them in the wild doesnt mean that it cant happen
Looking at any species, there is considerable variation in size and color (of the bills and the birds themselves) between individual birds... I don't think anyone could really tell the difference between a hen cinny and a hen blue-wing in hand without genetic testing... I could be wrong though...
If a duck is closely related (being from the same genus) then they are fertile. Bluewing, cinnamon and spoonies are from the same genus. They are then able to produce fertile offspring. Gadwall are from the same genus as wigeon. That's why a gadwall x mallard hybrid is sterile.
