My adult son recently gifted me with a pocket knife.
I hadn't carried one since I was a boy, and it took me back to my first knife, and the very first thing I learned to carve: a simple whistle.
You start with a small branch, cut off a section, notch it, slide off part of the bark, carve out a hollow and a flat spot for your breath to go through, replace the bark, and if all goes well it makes a very pleasing sound.
Of course, you have to know what you are doing, and you have to actually do it.
That's the difference between a whistle and a piece of a branch.