Definition of whistlers:
(n) :
Someone or something that whistles, or who plays a whistle as a musical instrument.
(n) :
Any bird that whistles or is noted for its whistling vocalisations (applied regionally to various specific species).
(n) :
Any of several passerine birds of the genera Pachycephala and Coracornis, of Australasia and the western Pacific.
(n) :
A goldeneye (any of certain ducks of genus Bucephala).
(n) :
A whistling marmot (Marmota caligata).
(n) :
A mountain beaver (Aplodontia rufa).