CONSISTENT INDIVIDUAL-DIFFERENCES IN EARLY EXPLORATORY-BEHAVIOR OF MALE GREAT TITS

Individual differences in early exploratory behaviour were investigated in hand-reared juvenile male great tits, Parus major, during the first 18 weeks of their life. The juveniles differed consistently in their reaction to a novel object in a familiar environment, either when tested with different objects or when tested again after 9 weeks. Birds that approached a novel object more quickly were also quicker to visit all artificial trees present in a novel environment than birds that approached a novel object more slowly. These behavioural differences extended to the strength of foraging habits, built up during a training period in which food was always offered at the same place. After a change in the location of food, the quicker birds would keep going to the place where the food used to be. The slower birds tended tb change their behaviour and stop going to the former place. The results show that juvenile male great tits differ consistently in various aspects of their exploratory behaviour at least during the first 18 weeks of life. The variation in behaviour was not likely to arise from differences in general activity or physical condition, but seems to refer to differences in the way in which information concerning the environment is collected and dealt with.