A shepherd's whistle is a specialized, multi-pitch whistle used to train and transmit commands to a sheepdog to aid in herding. Like a tin whistle, while simple, it can be used as a musical instrument in its own right.
A shepherd's whistle is traditionally used for managing working sheepdogs. They are typically seen used at sheepdog trials. Oral histories have noted primitive whistles made out of folding over a tobacco tin, a jam lid, or dog-food lid and punching a hole.
The whistle's design is best described as a flat circle of material, folded in half on a center line. This forms a very narrow U-shape in cross-section. The visible faces are typically a half-moon shape, although the design can be varied and the faces can be squarish, rectangular, or even a triangular A-shape. The open space between the two sides is quite narrow - approximately 4–5 mm. A hole is drilled through the center line of the two faces. The open side of the U is the mouth of the whistle - where the air exits. The bottom of the U is held against the tongue when in use. The size of the circle can vary, but typically will be from 45–65 mm across.
Mechanics and material
Unlike other whistles, they are placed inside the mouth and the pitch is controlled by placement of the tongue behind the whistle. They are commonly made of plastic, aluminum, stainless steel, silver, brass, titanium, corion, jade, buffalo horn and other materials.
Shepherd's whistles are used to communicate clearly and at distances up to several hundred yards the commands of the owner to his working dog. They produce clear, high-frequency tones of an easily modulated and variable pitch, allowing the shepherd to communicate a variety of commands. The pitch is at an optimal frequency for the herding dog's hearing, and for penetration and distance to cut through adverse weather when gathering sheep.
The whistle works by placing the tongue against the bottom, closed side of the whistle, to create a pocket of air between the whistle, the tongue, and the bottom of the mouth. Air is blown through, exiting through the top hole, and flowing across the bottom hole, which creates the sound. The mechanics of this action is similar to that which one uses when making sound by blowing over the lip of a bottle or jug, or when using a typical referee's whistle. Unlike typical, single-tone whistles, the shepherd's whistle can emit a range of tones, by using the tongue and mouth to change the shape and size of the resonance chamber.