Is risk-taking behaviour consistent throughout different threats?:Measuring among-individual variation in a population of blue tits

Among-individual variation in behaviours closely related to fitness, such as risk-taking behaviours, is found across the animal kingdom. However, its ecological drivers are poorly understood. Theoretical work suggests that individual differences in investment into current versus future reproduction may lead to a“slow-fast” continuum, known as the “pace-of-life syndrome” (POLS) hypothesis. Accordingly, populations may show variation among individuals in the level of risk-taking behaviours (i.e., "fast” individuals tend to take more risks and invest more in current breeding endangering their own survival as opposed to “slow”individuals). In addition, it has been suggested that consistent differences in individual risk-taking behaviours are repeatable across various threatening contexts. Yet, empirical studies in a natural setting remain scarce. The objectives of this study are: (1) to establish to what extent levels of risk-taking are repeatable in blue tits (males and females) across different contexts, and (2) to investigate how the variation in risk-taking relates to levels of parental investment. We will assess this hypothesis in a wild blue tit (Cyanistes caeruleus) population using two risky contexts during the nestling stage: (1) presenting a Eurasian sparrowhawk (Accipiter nisus) model as a predator stimulus, and (2) temporarily removing one parent bird to simulate a predation event. In both cases, to quantify the variation in risk-taking behaviour,we will use the latencies of birds to resume brood provisioning after having been exposed to the threat.Furthermore, we will collect fitness-related data (e.g., egg-laying date, clutch size, offspring survival) to investigate the fitness consequences of this behaviour. As predicted by the POLS hypothesis, we expect risk-taking behaviour to be consistent and repeatable in the individuals under different contexts.Moreover, we predict individuals that take more risk to have higher breeding success, as they invest more in their current reproduction (at the cost of their own survival)