Behavioral responses of black-headed gulls (Chroicocephalus ridibundus) to artificial provisioning in China

Feeding birds is a widespread and popular activity that affects almost all aspects of bird ecology. However, few studies are concerned about the impacts of human provisioning on bird behavior. In this study, we compared the foraging distance (FD) and flight initiation distance (FID) of the black-headed gull (Chroicocephalus ridibundus), a bird that is widely distributed in urban and rural areas in Kunming, China, under different artificial provisioning intensities. We also conducted a quantitative analysis of the relationship between artificial provisioning and behavioral changes in these birds. Our results showed that both the FD and FID of black-headed gulls in urban regions are significantly shorter than those in rural populations. Moreover, urban black-headed gulls exhibited a series of signs of domestication, such as actively approaching humans to beg for food and foraging when called or fed by humans, besides a reduction in FID. This suggests that provisioning by humans has caused black-headed gulls to be less fearful of humans and has reduced their defenses against predators. We recommend that bird feeding should be carefully and properly executed, and that the long-term effects of artificial provisioning on wild birds require further monitoring. (C) 2019 The Authors. Published by Elsevier B.V.