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

Individual differences in early exploratory behaviour were investigate d in hand-reared juvenile male great tits, Parus major, during the fir st 18 weeks of their life. The juveniles differed consistently in thei r reaction to a novel object in a familiar environment, either when te sted 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 a pproached a novel object more slowly. These behavioural differences ex tended to the strength of foraging habits, built up during a training period in which food was always offered at the same place. After a cha nge 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 th eir behaviour and stop going to the former place. The results show tha t juvenile male great tits differ consistently in various aspects of t heir exploratory behaviour at least during the first 18 weeks of life. The variation in behaviour was not likely to arise from differences i n general activity or physical condition, but seems to refer to differ ences in the way in which information concerning the environment is co llected and dealt with.