In Great Britain, sheepdog handlers use whistles to send orders to their herding dogs. Most of them use what called a "sheperd whistle", which are totally handsfree and can provide different tones (like this one or like the one used by Mr. Job Te Pas in this video)
Anyway, some sheepdog handlers used to whistle a nose flute for their job, but as we previously noticed in this post, they were (are) very few, because the nose whistles « obviously did not become popular ».
However, it was not the first time I met a shepherd nose whistle: I had previously "missed" this one:
The flute was handcrafted, and some of the lines that have been drawn with a awl on the metal sheet are still visible. Even the nose hood shows some of those tracés, and we can still see a middle circle that was engraved between the two air holes.