I think I can enlighten you guys again. I have seen many of this type of mallard hybrid and have them show up every once in a while. It is a mallard crossed with a Black East Indies duck. The black east Indies is a tame sport if you will. It is a totally melanistic mutation of a common mallard that breeds true to color . When bred back to a pure mallard they usually are blackwith white splotches on neck and throat. If you cross the first offspring back to a mallard again then you get the green head on the drake with rusty brown sides and belly. The Black East Indies is a tame duck that is bred for show or novelty.