Many Eyes Together: Investigating the Perceptual, Cognitive, and Social Foundations of Collective Detection in Bird Flocks

Social information use is considered one of the key benefits of group living. In the context of predation, group members can rely on each other’s vigilance to detect approaching threats in a process known as collective detection. Despite its intuitive appeal, the mechanisms underlying predator detection and information transfer remain poorly understood. The roles of vision and social cognition in this context have received limited attention, partly due to technical challenges. To address these questions, this thesis adopts an interdisciplinary approach, moving beyond traditional behavioral ecology to integrate insights from sensory ecology, cognition, collective behavior, social learning, and technological innovation. Motion-capture tracking of pigeons during simulated predator events revealed that the first “foveation” (directing their high-acuity visual area) toward a predator serves as a reliable indicator of detection, as well as how this detection relates to vigilance and escape responses. In another experiment, it was demonstrated that pigeons follow the gaze of conspecifics, with the strength of their response increasing as more individuals orient toward the stimulus. Finally, a Bayesian diffusion model showed that pigeons use peripheral vision to monitor others’ gaze direction and detect predators, supporting gaze following as a functional mechanism for social information transmission in collective predator detection. In addition to providing the first empirical evidence of gaze following as a functional mechanism in this context, these results demonstrate that pigeons can interpret subtle social cues during collective vigilance. Together, the findings uncover the perceptual and cognitive bases of predator detection and social information use within the collective vigilance context, and emphasize the value of interdisciplinary approaches for understanding the adaptive benefits of group living.