Visually guided pecking in the pigeon (Columba livia)

High-speed cinematography was used (1) to analyze the sequence of head movements made by pigeons pecking at small visual targets and (2) to determine where on the retina the target fell at different points in the sequence. In both key-pecking for food reward and normal feeding, the decision to peck the target was made during a head fixation that occurred over 80 mm from the surface on which the target was located (as measured from the center of the eyes). Once the decision to peck had been made, a second fixation (F2) occurred at an average distance of 55 mm allowing the bird to calculate the size, depth, and location of the target. Moreover, during both fixations, the target was located in the pigeon's binocular field within a region corresponding to the red area of the upper temporal quadrant of the retina.