Good news,
Elizabeth Creith, there doesn't seem to be
a preexisting word to singularly describe your particular skill.
Soooo...
How about
Whistlemaster or
flutemasters?
Or maybe,
whistlecrafter or
windmaker (naw, forget windmaker. people are so crude)
Let's see...we could suffix -artisans...
whistleart?
No? Ok, how about
whistlesudras, you know, after India's lowly artisan caste?
Me, personally, I like the Germanic sounding...
guildersflute.

But best of all, I like...
whistlemysteries.
Definition: my-ster-ies
(archaic) craft making What do ya think?