Birds’ Flight Initiation Distance in Residential Areas of Beijing Are Lower than in Pristine Environments: Implications for the Conservation of Urban Bird Diversity

Abstract

(1) Background: With rapid urbanization, birds are facing a variety of challenges. Evaluating bird behaviour changes in response to urbanization can help us understand how to make them coexist sustainably with humans. We aimed to investigate whether birds inhabiting residential areas differed in their escape behaviour and their influencing factors. (2) Methods: We used the flight initiation distance (FID), the horizontal distance between the observer and the target bird when it escapes, to measure the escape behaviour of birds. We chose 40 urban residential areas within the 5th ring road in Beijing and conducted surveys each month for one year. We applied Generalized Linear Mixed Models (GLMMs) separately to evaluate the response variable of FID for the total species, the most common species, and the other species. (3) Results: Birds that appear more frequently in residential areas or as ground foragers, insectivores, and omnivores are better adapted to human interference and have shorter FIDs. Individual initial conditions affect bird FID, and environmental characteristics can be used as predictors for the most common birds. Tree canopy coverage was found to positively affect FID, while floor area ratio (FAR) is negatively correlated with FID. (4) Conclusions: Our results demonstrated that birds in residential areas have been adapting to the human environment, and urban tree canopies can provide refuge for birds to avoid human interference. Our study focused on the response of bird FIDs to human interference and urban trees under high urbanization, which has substantial practical implications for urban managers to improve habitat quality to ensure that birds coexist with human beings.