I like to think that it also expresses the generic character of people who like to whistle, and although I know it can sometimes be intolerable to have a habitual siffleur in the family, forever performing " Pedro the Fisherman, " I still mourn the decline of the whistlers.    From Wordnik.com.  [You Know How to Whistle, Don] Reference

Others bark like 'toy-dogs,' while still other kinds utter a whistling noise, from which one species derives its trivial name of 'whistler' among the traders, and is the 'siffleur' of the Canadian voyageurs.    From Wordnik.com.  [Popular Adventure Tales] Reference

Others bark like ` toy-dogs, 'while still other kinds utter a whistling noise, from which one species derives its trivial name of ` whistler' among the traders, and is the ` siffleur 'of the Canadian voyageurs.    From Wordnik.com.  [The Young Voyageurs Boy Hunters in the North] Reference