Visual field organization and peck localization in the pigeon (Columba livia)

Some aspects of the stimulus control of peck localization in the pigeon were examined using conditioning paradigms, visual occlusion procedures, and 'touch-screen' technology. Birds were reinforced for pecks made to a small circular (target) stimulus projected upon a computer monitor and located within an electronically defined contingency area. The terminal location of each peck was monitored under binocular and monocular viewing conditions and when using either the frontal or lateral visual fields. Peck localization was highly accurate under either binocular or monocular viewing conditions or with the frontal field alone; there were no systematic differences between the right and left eyes and differences between monocular and binocular localization performance, though significant, were minimal. When viewing with the lateral field alone, subjects were initially unable to locate the food hopper and, even after retraining, conditioned peck localization was profoundly disrupted. The results confirm previous reports of functional differences between the frontal and lateral visual fields, but suggest that monocular cues are sufficient for highly accurate peck localization.