Variation in reactions to aposematic prey is common among conspecific individuals of bird predators. It
may result from different individual experience but it also exists among naive birds. This variation may
possibly be explained by the effect of personality—a complex of correlated, heritable behavioural traits
consistent across contexts. In the great tit (Parus major), two extreme personality types have been defined.
‘Fast’ explorers are bold, aggressive and routine-forming; ‘slow’ explorers are shy, non-aggressive and
innovative. Influence of personality type on unlearned reaction to aposematic prey, rate of avoidance
learning and memory were tested in naive, hand-reared great tits from two opposite lines selected for
exploration (slow against fast). The birds were subjected to a sequence of trials in which they were offered
aposematic adult firebugs (Pyrrhocoris apterus). Slow birds showed a greater degree of unlearned wariness
and learned to avoid the firebugs faster than fast birds. Although birds of both personality types remembered
their experience, slow birds were more cautious in the memory test. We conclude that not only
different species but also populations of predators that differ in proportions of personality types may
have different impacts on survival of aposematic insects under natural conditions.