Differing nest-defence behaviour in urban and rural populations of breeding Burrowing Owls

Abstract

The behaviour of birds in urban habitats often differs from that of birds in surrounding natural and rural habitats, with the attenuation of fear responses to humans a primary behavioural adaptation to urban life. In breeding birds, fear responses and nest-defence have been linked to reproductive success. We studied the nest-defence behaviour of male Burrowing Owls in rural and urban habitats by measuring flight-initiation distance (FID), time to return to the nest following disturbance and aggressiveness of nest-defence in response to a person walking towards them during three stages of their breeding period: during incubation and during two nestling stages. Male Burrowing Owls breeding in rural habitat had longer FID than Owls breeding in urban habitat, but FID did not decrease over the breeding season whereas it did decrease over the breeding season in urban habitat. Male Owls in rural habitat were less likely to return to their nests within 10 min of disturbance than Owls in urban habitat. Lastly, aggressiveness of nest-defence of Owls breeding in rural and urban habitats was similar and increased throughout the breeding season in both habitats. Our results highlight the role of behaviour in explaining the ability of Burrowing Owls to live in a range of habitats, including successfully breeding in urban areas, and emphasise the importance of breeding stage on behavioural traits.