A male black duck.
black duck definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a sooty brown, wild duck (Anas rubripes) of E North America
black duck definition by American Heritage Dictionary
A common duck (Anas rubripes) of the northeast United States and Canada, characterized by black or dusky brown plumage and often found in saltwater marshes.