OF GREAT TITS AND FLEAS - SLEEP BABY SLEEP

Many bird parasites reduce their hosts' fitness and, as a consequence, anti-parasite behaviour such as preening and nest sanitation has evol ved. These activities are time consuming and, during the day, compete directly with time devoted to foraging and food provisioning to nestli ngs. Moreover, infested hosts may have to allocate extra time to forag ing in order to compensate for the energy loss that ectoparasites impo se on the nestlings and parents. Alternatively, brooding females could , at the expense of sleeping, allocate more time to preening and nest sanitation at night. If sleeping has a short-term restoring function, one may then expect a reduction in feeding efficiency of sleep-deprive d females. In this study, the effect of a haematophagous ectoparasite, the hen flea, on the activity budgets of breeding female great tits d uring the day and at night was investigated experimentally. Time alloc ated to nest sanitation increased only slightly from 0.6 % of daytime in ectoparasite-free nests to 2.8% of daytime in infested nests, thus demonstrating the higher priority given to food provisioning than para site control. Females in infested nests reduced their sleeping time si gnificantly (73.5% of night-time in parasite-free nests versus 48.1% i n infested nests). The time freed from the reduction of sleeping time was mainly used for nest sanitation (8.3% of night-time in parasite-fr ee nests versus 27.1% in infested nests). Despite this strong decrease in sleeping time, there was no effect of ectoparasites on the females ' rate of food provisioning to nestlings. (C) 1996 The Association for the Study of Animal Behaviour