Nestlings of two parrotbill species can independently evaluate the presence of predators based on acoustic cues

Nest predation is the leading cause of reproductive failure in birds and a major driving force in the evolution of anti-predation strategies. Current studies on the anti-predation strategies of birds driven by predation pressure have mainly focused on adults. However, the detection and behavioral responses of nestlings toward predation risk require further investigation. In this study, we examined nestling responses to predator sounds. Two species of nestlings, the Reed Parrotbill (Paradoxornis heudei) and Vinous-throated Parrotbill (Sinosuthora webbiana), were exposed to the Sparrowhawk (Accipiter nisus, less common) and Oriental Magpie (Pica serica, more common), which are predator species, the Oriental Turtle Dove (Streptopelia orientalis), which is a commonly found harmless species, and background noise. Our findings revealed that compared to pre-playback of natural begging and playback of background noise and Oriental Turtle Dove sounds, playback of the two predator types decreased the total begging time and total number of calls of the two nestlings species, with the calls of the Sparrowhawk leading to greater suppression of nestling begging behavior than those of the Oriental Magpie. Therefore, our results indicated that these nestlings were able to distinguish predators from harmless species based on auditory cues.