When twisted, this simple birch wood/pewter instrument will produce sounds which attract a variety of wild songbirds. It is now the standard songbird call throughout the world. The Audubon Bird Call comes packaged with a capsule of rosin powder.The bird call’s sound is produced by twisting the cast zinc plug against the wooden cylinder. Originally used by hunters in Europe, the bird call’s sound attracts birds by convincing them that there are other birds in the area. They are curious about the sound.