This is actually a Northern Black-bellied Whistling Duck, even though it resides in the south. Up until recently it was not around the Lowcountry. Now it breeds here.
This duck is most common in South America.
Similar to the American Wood Duck they prefer to nest in trees. Once the young are hatched they are out in the grasses and water.
Just to confuse the bird watchers, a few hundred live year round in the parks of New Orleans, LA.
More proof those maps in the back of the bird books are not all that accurate.