Subtle cues of predation risk: starlings respond to a predator's direction of eye-gaze

摘要

For prey animals to negotiate successfully the fundamental trade-off between predation and starvation, anrealistic assessment of predation risk is vital. Prey responses to conspicuous indicators of risk (such asnlooming predators or fleeing conspecifics) are well documented, but there should also be strong selectionnfor the detection of more subtle cues. A predator’s head orientation and eye-gaze direction are goodncandidates for subtle but useful indicators of risk, since many predators orient their head and eyes towardsntheir prey as they attack. We describe the first explicit demonstration of a bird responding to a livenpredator’s eye-gaze direction. We present wild-caught European starlings (Sturnus vulgaris) with humann‘predators’ whose frontal appearance and gaze direction are manipulated independently, and show thatnstarlings are sensitive to the predator’s orientation, the presence of eyes and the direction of eye-gaze.nStarlings respond in a functionally significant manner: when the predator’s gaze was averted, starlingsnresumed feeding earlier, at a higher rate and consumed more food overall. By correctly assessing lower risknand returning to feeding activity earlier (as in this study), the animal gains a competitive advantage overnconspecifics that do not respond to the subtle predator cue in this way.