Some of these characteristics were consistent with this New York mallard. So, I contacted Dr. Mike Brasher from Ducks Unlimited, and he put me in touch with the relatively new duckDNA program.

Male mallards make a softer, rasping sound ... of human actions on the mallard’s biology. Until the early 1900s, for example, this most common species of duck was actually quite uncommon ...

Black ducks are often found mixed in with flocks of mallards. They also make very similar sounds to their mallard cousins. The hens quack, and the drakes have a high, quiet, nasal quack.