Hold the metal ring with one hand, and turn the wooden sphere with light pressure using the other hand. Do this with variation and different speeds. Only a short movement is necessary to imitate the call of the robin. Repeat the movement several times.
See video below.
Delivered in handmade wooden box.
Video: French Francois Morel shows here how the bird sound is produced. Francois Morel is an ornithologist and has been producing bird calls since 1975. Read more about the production of bird whistles.