in order to determine the answer to the four proposed questions, marcel and andré recorded male great tits from 1983-1986 in two plots (l and b) in the peerdsbos and another plot (u) on campus at the university of antwerp in wilrijk. they came up with the anti-exhaustion hypothesis as an explanation for the results obtained from their study. their results showed that high quality males, as predicted, had a higher percentage performance time than low quality males. lambrechts and dhondt also found that all great tits can show a systematic decrease in the percentage performance time during a bout, which is also known as drift.