Q. (See questions 2804-6 above regarding whistling on Shabbos). Is there any truth in what people say that whistling calls sheiddim?
A. Rivavos Efraim (O.H. 8: 424) indeed mentions this question, and he answers that although his Rebeh in cheider said that it is prohibited to whistle, he does not know the source for it.
From the rulings of the Shulchan Aruch (O.H. 338: 1, mentioned on the prior questions) that it is permitted to whistle with one's mouth on Shabbos, it would seem that there is no prohibitive issue with whistling. Still there seems to be a widespread tradition especially for those following Chassidic traditions, to avoid whistling altogether. There is an old saying often repeated by those familiar with Yidish old sayings, that 'Yiden faifen nisht or Jewish people don't whistle." There is also a saying that the Hebrew verb for whistling is "sharak," which positions the almost last words of the alef beis backwards. thus symbolizing the incorrectness of the act.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit'a