Making an Elder whistle

In this Tutorial I used fresh Elder wood that was still green. It is best to use dry dead wood, otherwise the wood may shrink and cause the whistle to stop working. The construction of the whistle is exactly the same if you use dry wood which I recommend.
We are taking advantage of elder wood because it has a very soft pith which can be easily removed to create a hollow tube.

To help you with your tree identification I have taken these photos of some Elder so that you know what you are looking for. The picture on the left shows typical thinner branches and leaves whereas the picture on the right shows the thicker trunk of the tree. Elder usually grows only a few meters tall and tends to grow in poor quality soil.
 
Cut a small branch that is already the correct width. You can see how thick this piece is in comparison to my fingers.
It is important that the wood has a large pith in the centre because this will make plenty of room for the sound chamber, however you will want the layer of wood to be thick enough so that it is not fragile. A shoot of wood about 2 years old is usually good. You may have to cut several branches before you find the perfect piece of wood.
Cut a section from your wood about a finger long.
Scrape the bark off if you like.
Push the pith out and scrape the inner walls with a small stick until totally free of pith.
About 2cm in from the end you need to cut a notch in the whistle, a few cuts at 90 degrees and then some more at 45 degrees. The pictures explain it all...
Now you need to make a small piece of wood to fit into the mouth end of the whistle. Carve a stick down to make dowel the correct diameter to fit the inside of the whistle. Test how well it fits by pushing it into the end of the whistle.
To create the air passage carve a flat face on the side of the dowel.
Cut the small piece of dowel to the correct length. (as long as from the mouth end of the whistle to the vertical cut of the notch)

The dowel should be a tight fit and will need no glue if it fits snugly.

Fit the dowel so that when you blow through the small gap the air runs level with the notch.
Once you have fitted the dowel in the end you could carve the mouth end to a better shape if you like.
You can see how the air passage is created by the flat side on the dowel.

At this point you can test the whistle to see if you get a sound. Put your finger over the other end to block it, then blow the whistle. You should get a nice clear sound.
If you get sound you can block up the other end of the whistle with another piece of wood. Do the same as before but don't carve the side flat. No air should be able to pass through this end.

You get a higher pitched sound if you make the sound chamber smaller.
Your whistle is complete. You could add a loop of cordage so that it can be put onto a key ring if you like...