Expiratory muscle activity during song production in the canary

Elaborate respiratory patterns accompany song production in male canaries (Serinus canaria). To learn how such patterns arise, electromyographic activity was measured in the expiratory muscles in the abdomen. Most song phrases are accompanied either by mini-breaths (when syllable repetition rates are 2 to 27/sec) or by pulsatile expiration (when syllable repetition rates are 30 to 38/sec). In both cases there is a one-to-one correspondence between bursts of expiratory muscle electrical activity and song syllables. Phrases with syllable repetition rates of 62-70/sec, which are rare, are accompanied by expiratory airflow that may be either pulsatile or continuous. The expiratory muscles are active throughout such phrases, suggesting that the muscles of the vocal organ, the syrinx, are responsible for producing separate notes. Thus, at rates up to 38/sec, the abdominal muscles of canaries contract briefly for the production of each song syllable.