coscoroba

from The Century Dictionary.

• noun A large swan-like duck, Coscoroba coscoroba, of South America, which has a white body and a long, slender, black neck.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) A large, white, South American duck, of the genus Cascoroba, resembling a swan.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun large white South American bird intermediate in some respects between ducks and swans