Professional whistlers were common during the turn of the last century and were recorded commercially. I have one 78 of a woman doing "Whistling Rufus" backed by Arthur Pryor's Band, a very popular concert band at the time. I forget her name, I'll look it up tomorrow. I also have a recently recorded CD of a Norwegian professional whistler doing everything from traditional tunes to a Rossini overture. It's upstairs, so I'll look up his name tomorrow.