Kluijver H.N. (1950) Daily routines of the Great Tit, Parus m. major L.. ARDEA 38 (3-4): 99-135

Times of rising and retiring for the day. a. The reproductive period. During the whole period of reproduction the female sleeps in the nest cavity, the male sleeps outside. He starts his daily activity earlier than the female and calls her out by song. During the laying and the brooding period the female rises on an average 20 minutes after sunrise; as soon as the young have hatched she rises 6 minutes before sunrise. In April and May the male starts singing on an average 37 minutes before sunrise. The female retires very early to roost, viz. 64 minutes before sunrise during the laying period and 100 minutes before sunrise during the brooding period. After the young have hatched the moment of last activity of the female gradually moves to sunset. b. Summer, autumn and winter. During November, December and January the beginning of the activity starts on an average 26 minutes before sunrise, the extremes being 14 and 40 minutes before sunrise. This variability is due to differences in wind speed; temperature and cloudiness. The male rises 2 minutes earlier than the female, he remains active 12 minutes longer than she does. In August the birds go to roost an hour before sunset, in winter at sunset, only in December slightly after it. These differences are connected with day-length and food requirements. Weather conditions are of little influence on the time of retiring. Time spent on and off the eggs. a. The laying period. In the first brood no brooding takes place during the day time. The female only visits the nest now and then for nest building. She abandons it, however, usually within a minute. Brooding begins after the last. egg is laid. In the second brood the female sits on the eggs on the 5th day for an hour during the daytime. Before the clutch is completed she broods 8 hours during the day. The fact that in the second brood the young hatch over a longer period is related with this early start of brooding. During the night the female sits continually on the nest and the eggs reach a temperature of 33¦ C, besides 36¦-39¦ C during the incubation period. b. The incubation period. The female exclusively broods the eggs. During the day time the length of the periods which a female spent on the eggs amounted to an average of 27.6 minutes, the length of the intervals was 7.9 minutes. In the second brood ,these periods were respectively 26.2 minutes and 10.9 minutes. The longest period of perpetual brooding was 68 minutes. The number of interchanges diverged between12 and 29 per day. During the first days of the incubation period the female gradually changed from no brooding at all to full capacity. The low number of brooding hours during the first days is mainly the result of no brooding in the morning. The brooding attentiveness of the female decreases if air temperature rises. Feeding. During the incubation the male feeds the female in or out the nesting hole. The number of feedings per day is relatively low. On the day of hatching of the. young the male immediately starts with the food supply. The female takes up this task only gradually. In the first brood of a pair the number of feedings increased successively from 120 on the first day to 937 on the 16th day (10 young). The total number of feedings amounted to 10,685 (1,068 per nestling). In the second brood of the same pair the parents started with 52 feedings on ,the first day and the number increased to a maximum of 256 on the 11th day (7 young). The total number of feedings amounted to 4,042 (577 per nestling). The difference in number of feedings is connected with the fact that insects are larger in June and July than in May. Nestlings of other broods received different numbers of feedings (see table 6). Feeding activity of the parents is greater in the morning than in the afternoon. The afternoon minimum is usually found on the level of 60 % of the morning maximum.