A further look at the binocular visual field of the pigeon (Columba livia).

The binocular visual field of the pigeon, measured ophthalmoscopically, is ovoid in shape. It is 114 degrees in vertical extent and centered and widest (37 degrees) about the eye-beak axis (i.e. the line passing through the straight edge of the beak and the midpoint of a line connecting the centres of the pupils). The area dorsalis projects 10 degrees-15 degrees below the eye-beak axis where the field is 35 degrees wide. The stereotyped peck response of the pigeon entails birds pausing twice. At the first fixation, the image of a grain is on the area dorsalis and at the final fixation the grain is centered within the widest part of the binocular field.