Syringeal Anatomy in the Common Crow

Abstract

Careful dissections of 55 Common Crows collected in the field revealed that four pairs of bronchial rings, five tracheal rings, one pair of external tympaniform membranes, one pair of internal tympaniform membranes, one pair of auxiliary membranes, and six pairs of muscles are the components of sound production in the syrinx. They function by adjusting the distance between the external and internal tympaniform membranes and by adjusting the tension on the external tympaniform membrane. Experiments on dissected crow syringes show that sound is produced by air currents passing anteriorly through the respiratory tubes, thereby eliciting vibrations in the external tympaniform membranes.