Flock size does not influence escape decisions of urban lawn-foraging birds

Abstract

Context Predator avoidance is considered a key evolutionary driver shaping aggregation behavior. An overlooked aspect in the study of predator avoidance is whether individuals can make better escape decisions (i.e. gain greater benefits) when in larger groups. Escape decisions encompass when to flee (FID: the distance at which an animal moves away from approaching threats), how far to flee (distance fled, DF), flight direction (FD) and whether to seek refuge. Aim This study evaluates the influence of flock size on the FID, DF and FD in urban birds. Methods We studied a series of escape behaviors of eight urban lawn-foraging bird species in Huaibei city, China, approached by one, two or three persons representing varying levels of predation risk. Key results We found that flock size had a limited effect on birds’ escape decisions, including FID, DF, FD and refuge-seeking behavior, with some species-specific effects. Predation risk (number of approachers) also had a subtle influence on birds’ escape decisions. Conclusions Urban birds generally exhibit consistent escape behavior regardless of flock size or predation risk. Implications Urban birds might maintain a minimum antipredator response to approaching humans due to their extensive habituation to human occurrence. Future research should examine how urban birds’ responses to humans compare with their reactions to natural predators, and investigate the varying impacts of urbanization on these behaviors.