Escape ability and risk-taking behaviour in a Hungarian population of the collared flycatcher (Ficedula albicollis)

Abstract

Risk-taking decisions in front of a predator are crucial for the fitness of the animals. Risk-taking behaviour can be hypothesised to depend on escape ability, which is difficult to study in the wild. In this field study, we investigated whether escape ability (i) is a consistent individual-specific characteristic and (ii) can explain between-individual variation in risk-taking behaviour in male collared flycatchers (Ficedula albicollis). We estimated escape ability by the time that was needed to capture individuals by hand in an outdoor aviary during both the courtship and the nestling feeding phases. We estimated risk-taking by human-induced flight initiation distance (FID) and parental nest-defence behaviour. We also measured variables that reflect individual quality and condition to assess how these affect escape ability. Time to capture was weakly repeatable in the within- and between-season contexts, but was considerably repeatable within a day. We found that time to capture decreased between courtship and nestling feeding phases, probably due to parallel changes in body condition (as shown by the systematic decline of individual body mass between phases correlating with within-individual changes in time to capture). Overall, time to capture was not significantly related to risk-taking behaviour, but we found a negative correlation between time to capture and FID in yearlings. In conclusion, escape ability in flycatchers seems to be a condition-dependent plastic trait, and it has the potential to affect immediate risk-taking decisions. We investigated the proximate determinants of escape ability in collared flycatcher males and whether this trait can be a potential driver of risk-taking behaviour, which is a rarely considered issue. We measured escape ability as time needed to capture birds in an outdoor aviary by hand. We found that escape ability was repeatable only in a short-term context, and differed between the courtship and chick-feeding periods, probably due to parallel changes in body condition. Furthermore, escape ability in yearlings (but not in adults) correlated with an estimate of risk-taking in the wild indicating that males with better ability to escape take higher risk. Our findings highlight that individual decisions about risk-taking might partially rely on how individuals assess their potential escape success.