What are birds looking at? A large-scale motion-capture system reveals the visual attention of freely- behaving pigeons

Abstract

Using a large-scale motion-capture system and custom head-calibration methods, we reconstructed the head-centric view of freely behaving pigeons and examined how they orient their head when presented with various types of attention-getting objects at various relative locations. Pigeons predominantly employed their retinal specializations to view a visual target, namely their foveas projecting laterally (at an azimuth of ±75°) into the horizon, and their visually-sensitive “red areas” projecting broadly into the lower-frontal visual field. Pigeons used their foveas to view any distant object while they used their red areas to view a nearby food-related object on the ground (< 50 cm). Pigeons “fixated” a visual target with their foveas; the intervals between head saccades were longer when the visual target was viewed by birds’ foveas compared to when it was viewed by any other visual field region. Furthermore, pigeons used their right eye to observe food-related objects and their left eye to do so for threat-related or social stimuli. Despite the known difficulty in identifying where a bird is attending, we show that it is possible to estimate the visual attention of freely behaving individuals by tracking the projections of their retinal specializations in their visual field with cutting-edge methods.