Traditional assessments of anthropogenic impacts on biodiversity often ignore hunting pressure or use subjective categories (e.g. high, medium or low) that cannot be readily understood by readers or replicated in other studies. Although animals often appear tame in habitats without hunting compared to habitats with hunting, few studies have demonstrated such effects. We determined the flight initiation distance (FID; i.e. human-animal distance when the animal begins to flee) of a common frugivorous bird of Southeast Asia, Sooty-headed Bulbul (Pycnonotus aurigaster) across a gradient of hunting pressures in Xishuangbanna, Yunnan, SW China. Controlling for confounding effects, we show that FID increased with hunting pressure, which was quantitatively measured through encounters with hunters. As FIDs respond more specifically to hunting than other defaunation metrics, we suggest they can be used as behavioral indicators of hunting pressure in developing conservation strategies.
