Individual behavioural characteristics and dominance in aviary groups of great tits

In previous work we have shown that juvenile male great tits Parus major show consistent behavioural differences in exploratory and aggressive behaviour. Fast and superficial explorers (FE) won from slow and thorough explorers (SE) during controlled pair-wise confrontations in small cages. The present study assesses the relationship between early exploratory behaviour and later dominance in aviary groups of juvenile male great tits; such groups might approach natural conditions better than 'simple' pair-wise confrontations. Observations of nine aviary groups showed that a stable hierarchy is only established after a first dynamic phase of several days with many dominance shifts and a peak in number of interactions. In seven other aviary groups we determined the dominance relationships between FE and SE. In a stable hierarchy, SE had on average a significantly higher dominance score than FE. This finding contrasts our previous results in pair-wise confrontations. However, on the first day in the aviary, FE had on average a higher dominance score and initiated more fights than SE. This agrees with our previous results and indicates a gradual development of the situation in the stable hierarchy. Behavioural observations indicate that during this development, FE took more risks in their fighting behaviour and had more difficulty to cope with defeat than SE. In the stable hierarchy they either won or lost from all SE. SE were more cautious and had intermediate dominance scores in the stable hierarchy. These differences in fighting behaviour and the role of individual differences in exploratory behaviour and in coping with defeat are discussed as possible causes for the unexpected results of this study.