Abstract
Urbanisation is a major land-use change that introduces novel disturbances and risks into ecosystems, requiring species to adjust their fear responses to avoid fitness costs associated with mismatched anti-predator behaviour. Successful urban-dwelling species often modify flight responses to balance risk avoidance with maximising access to human-associated resources. Here, we examined the impact of urbanisation on escape responses in Red-billed Gulls (Chroicocephalus novaehollandiae scopulinus), a nationally threatened species in New Zealand, using flight initiation distance (FID) as an indicator of boldness. We compared two urban sites, Dunedin and Oamaru, with one rural site, Taiaroa Head, and predicted that gulls in urban areas would exhibit shorter FIDs than those in rural environments, while adults would display shorter FIDs than juveniles and flocks. We recorded 705 FID observations across Dunedin, Oamaru, and Taiaroa Head in Otago, New Zealand. Dunedin gulls exhibited significantly shorter FIDs, while, contrary to expectations, Oamaru gulls showed longer escape distances like those in rural Taiaroa Head. Within Dunedin, FID varied across sub-habitats, with gulls in high-human-activity areas displaying shorter FIDs than those in less disturbed areas. Age and social dynamics also influenced escape responses, with juveniles and flocks exhibiting FIDs longer than adults, though this difference diminished in Dunedin. Gulls in Dunedin primarily used terrestrial escapes and anthropogenic refuges following disturbance, while rural gulls relied more on aerial escapes toward distant refuges. Our study suggests that growing Red-billed Gull populations in Dunedin are adapting risk perception and escape strategies to human-modified landscapes, reinforcing their persistence in urbanised environments.