The Collaborative International Dictionary of English v.0.48:

Whistling \Whis"tling\,
   a. & n. from Whistle, v.
   [1913 Webster]

   Whistling buoy. (Naut.) See under Buoy.

   Whistling coot (Zool.), the American black scoter.

   Whistling Dick. (Zool.)
   (a) An Australian shrike thrush (Colluricincla Selbii).
   (b) The song thrush. [Prov. Eng.]

   Whistling duck. (Zool.)
   (a) The golden-eye.
   (b) A tree duck.

   Whistling eagle (Zool.), a small Australian eagle
      (Haliastur sphenurus); -- called also whistling hawk,
      and little swamp eagle.

   Whistling plover. (Zool.)
   (a) The golden plover.
   (b) The black-bellied, or gray, plover.

   Whistling snipe (Zool.), the American woodcock.

   Whistling swan. (Zool.)
   (a) The European whooper swan; -- called also wild swan,
       and elk.
   (b) An American swan (Olor columbianus). See under Swan.


   Whistling teal (Zool.), a tree duck, as Dendrocygna
      awsuree of India.

   Whistling thrush. (Zool.)
   (a) Any one of several species of singing birds of the genus
       Myiophonus, native of Asia, Australia, and the East
       Indies. They are generally black, glossed with blue, and
       have a patch of bright blue on each shoulder. Their note
       is a loud and clear whistle.
   (b) The song thrush. [Prov. Eng.]
       [1913 Webster]

WordNet (r) 3.0 (2006):

whistling swan
    n 1: North American subspecies of tundra swan having a soft
         whistling note [syn: whistling swan, Cygnus columbianus
         columbianus]