Human-induced rapid environmental changes challenge individuals by creating evolutionarily novel scenarios, where species encounter novel enemies, the new species sometimes being humans themselves. However, little is known about how individuals react to human presence, specifically whether they are able to habituate to human presence, as frequently assumed, or are selected based on their fear of humans. We tested whether fear of humans (measured as flight initiation distance in a diurnal owl) is reduced through habituation to human presence (plasticity) or whether it remains unchanged throughout the individuals' life. Results show an unusually high level of individual consistency in fear of humans throughout the adult lifespan of both rural (r = 0.96) and urban (r = 0.90) birds, lending no support to habituation. Further research should assess the role of inter-individual variability in fear of humans in shaping the distribution of individuals and species in an increasingly humanized world.