In animals such as birds that are capable of adjusting energy reserves behaviourally in response to starvation risk and predation risk, mass is a measure of an individual's perception of the risks in its environment. Although it is often necessary to capture and handle animals to allow the scientific study of animal behaviour, little is known about how this affects the individual's perception of the risks in its environment or how this changes subsequent behaviour. In this study we remotely monitored the mass of individual wild great tits, Parus major, for 10 days after capture, handling and release and then used starvation–predation risk trade-off theory to investigate how individuals perceived the risks in their environment. Mass increased significantly after capture and remained higher for 7 days before returning to precapture levels. We conclude that the capture and handling event was perceived as an interruption to foraging induced by an encounter with a predator which heightened starvation risk. Although this forced interruption to foraging was a relatively small proportion of available foraging time (<6%), the subsequent response produced a large (66% of normal diurnal mass gain) and sustained change in mass. The results highlight the key role that foraging interruptions play in an individual's assessment of risks when trading off starvation against predation. They may also help to explain why some investigations of the effect of perceived predation risk on body mass in captive birds have produced inconsistent results.