Abstract: Investigating tolerance distance of common birds to human disturbances in urban areas can help to understand how they behaviorally adapt to the increasing urbanization that has significant impacts on wildlife. From March to May 2017, we measured alert distance, flush distance, buffer distance and safety distance of common birds in three sites with different degrees of urbanization in Hefei, China. Human disturbances and other environmental variables were also quantified. General linear model was used to test effects of environmental factors on tolerance distances of six species with large sample size. Pearson correlation analysis was used to test correlations among the four distances of each species. Results indicated that tolerance distances varied among species; oriental turtle dove has the longest tolerance distances, followed by spotted dove, common magpie, common blackbird, azure-winged magpie and Eurasian tree sparrow. Tolerance distances were negatively associated with human disturbances. Alerting distance and flush distance were longer in larger groups. Alerting distance, flush distance and safety distance were shorter when birds were closer to refuges. Birds on the ground appeared to be less tolerant than those in brush or trees. There were positive correlations among the four measured tolerance distances. This study showed that urban birds can modify their tolerance distances to intensive human disturbance in cities. According to our findings, we made suggestions on the management and conservation of common birds in the context of urbanization.

Key words: urban birds, human disturbance, alerting distance, flush distance