Silent dog whistles, also known as Galton's whistles, are excellent for getting your dog's attention in a crowded area, amid a lot of noise or wind, and without putting in the effort of yelling and chasing them down. Silent dog whistles are designed to emit a high pitch that only dogs can hear. You can train your dog to respond to these high-pitched noises. A dog whistle can be made in much the same way as a willow whistle, with a few alterations made to increase the pitch.
Find a willow tree branch 8 to 10 inches long and roughly three-fourths of an inch thick.
Cut one of the branches at a 45-degree angle. Cut off the sharp end piece squarely.
Make a hole in the top of the whistle with your knife, pushing the tip of your knife down into the branch. On the underside, bore out a small hole at an angle the same way as with the top hole. Make this hole no bigger than you could put the tip of a pen through.
Cut a line from the end of your mouthpiece along the bark for 6 inches. Cut a circle around the branch where your line ends and remove the bark. You can tap the branch against another piece of wood to help loosen the bark, but keep it in one piece.
Cut out a rounded trench in the top half of the whistle. A general rule is the deeper the whistle, the lower pitch the sound will be. Since you want a high-pitched whistle for a dog, this trench should be shallow. Cut no more than one-fourth the depth of the branch. Cut a small shaft the width of your knife blade across your mouthpiece toward the trench. This will be essential in producing the high-pitched sound.
Wet the exposed wood and reapply the bark, creating a chamber for the sound to resonate from. A good dog whistle will make a blowing sound barely audible to human ears, but dogs will hear it loud and clear.
Lightly reapply water to the incised strip of bark to renew the whistle sound.
Always cut away from your body when using a knife.