NFG: SOme further explanation.
I have made comments in various places, but I don't think there was enough space to get my point(s) across.
I don't like "mallard duck" for a couple of reasons. Firstly, to me, a "mallard duck" sounds like a female mallard. Secondly, if "duck" is just added to let the reader know that a mallard is a type (a species, not a breed) of duck, I think this is very bad form in a pretentious foodie context. You have to pretend that you and your reader are familiar with such matters as common game birds.
"Colvert" in French is really one word, meaning mallard. Etymologically, it refers to the green feathers on the head of the male (and only the male). The whole head is green actually, not just the feathers around the neck. So it is at least arguable that adding "green-collared" is translating something that's not there, although it does add a little colour....
Of course, once we take on board that only the drake has a green collar, then "green-collared mallard duck" becomes a ludicrous contradiction.
My final advice: keep the "green-collared" if you like, but lose the "duck".
As for "wild", the mallard is the wild species from which all domestic ducks are bred, but there would be nothing, I suppose, to stop someone from capturing a brace of mallard from the wild and raising first-generation domesticated mallards.... Besides, you can't object to at as a pleonasm, as it is already in the French, and just as much or as little a pleonasm there.