the anti-exhaustion hypothesis stated that when it is necessary for a bird to sing for a prolonged period of time at a high rate, it must continuously switch song types. the hypothesis was focused around the idea that extended bouts of singing would lead to neuromuscular exhaustion because of the repetitive and stereotyped fashion of song bouts. marcel and andré proposed that the male great tits would have longer inter-strophe pauses towards the end of a song due to this exhaustion. by switching song types, the birds would be using alternative sound-producing muscles and nerves, therefore they would be able to recover a high percentage performance once again.