Figure 1. Visual fields of Kiwi.

a, Perspective view of an orthographic projection of the binocular field as projected onto the surface of a sphere surrounding the bird's head. The grid shows conventional latitude and longitude at 20° intervals and the median sagittal plane of the bird's head is in the plane of the equator (which is vertical). The head is in the same posture as depicted in (c). b, Horizontal section through the visual field in the plane of maximum binocular field width which is the horizontal plane in (a) and (c). c, Drawing of a side view of a kiwi head, the bill tip projects 20° below the horizontal as shown in (a). Scale bar 40 mm.