Abstract
Assessing behavioural consistency is crucial to understand the evolution of personality traits. In the present study we examined the short- and long-term repeatability and stability of two unrelated personality traits—exploratory tendencies and struggling rate—using captive female zebra finches (Taeniopygia guttata). We performed two experimental sessions of behavioural tests with a seven-month interval, which represents up to one quarter of a zebra finch's life expectancy. We showed that, overall, exploratory tendencies and struggling rate were significantly repeatable in the short-term. However, only exploratory tendencies were repeatable in the long-term. We found inter-individual differences in short-term stability of exploratory tendencies, but not struggling rate, providing evidence for differences in intra-individual variability. In the long-term, struggling rate significantly decreased between the two experimental sessions, whereas exploratory tendencies remained stable. Finally, the amount of inter-individual variation measured at both sessions did not differ. Our results suggest that short- and long-term repeatability and stability of personality may vary between individuals, depending on the behavioural trait under scrutiny. As a consequence, deducing personality from measures realized earlier in a subject’s life should be performed with caution. We discuss the implications of inter- and intra-individual variation in personality consistency on individual fitness.