Conventional farming has been implicated in global biodiversity loss, with many farmland birds in decline. Organic farming is often considered a more ecological alternative since it generally hosts greater faunal diversity. To date, the impact of conventional agriculture on the decline in avian species has mainly been assessed through the lens of biodiversity loss; few studies have examined the effects of conventional farming on individual life-history trait components. Behaviour represents the final integrated outcome of a range of biochemical and physiological pathways and can be considered a proxy of health as it is more sensitive than other life-history traits, potentially allowing environmental changes to be better tracked. The goal of this study was to understand how exposure to conventional versus organic farming affects the behaviour of passerine birds in real conditions. By sampling 6 species of passerine birds in 10 hedgerows in organic landscapes and 10 hedgerows in conventional landscapes during the breeding period, we found evidence that organic farming sharply increased the vitality of individuals, irrespective of species. This was measured through behaviour such as flee attempts, aggressivity, pecking and distress calls when captured, all of which were higher in birds caught in organic hedges than those caught in conventional landscapes. We posit that passerines living in organically farmed landscapes benefit from reduced pesticide exposure rather than a greater abundance of food, as body condition was identical in the two contexts. These findings suggest that the behaviour of passerines can be a useful indicator of the state of the environment and can thus serve as an early warning of specific environmental change in agricultural areas. Further studies assessing the life-history traits of farmland birds may be a valuable aid to understanding the impact of conventional agriculture on biodiversity.