Editing Owl (section)

==== Vision ====
Eyesight is a particular characteristic of the owl that aids in nocturnal prey capture. Owls are part of a small group of birds that live nocturnally, but do not use [[Animal echolocation|echolocation]] to guide them in flight in low-light situations. Owls are known for their disproportionally large eyes in comparison to their skulls. An apparent consequence of the evolution of an absolutely large eye in a relatively small skull is that the eye of the owl has become tubular in shape. This shape is found in other so-called nocturnal eyes, such as the eyes of [[Strepsirrhini|strepsirrhine]] [[primate]]s and [[bathypelagic fish]]es.<ref name="Walls1942"/> Since the eyes are fixed into these sclerotic tubes, they are unable to move the eyes in any direction.<ref name="König1999"/> Instead of moving their eyes, owls swivel their heads to view their surroundings. Owls' heads are capable of swiveling through an angle of roughly 270°, easily enabling them to see behind them without relocating the torso.<ref name="König1999"/> This ability keeps bodily movement at a minimum, thus reduces the amount of sound the owl makes as it waits for its prey. Owls are regarded as having the most frontally placed eyes among all avian groups, which gives them some of the largest binocular fields of vision. Owls are farsighted and cannot focus on objects within a few centimetres of their eyes.<ref name="Walls1942"/><ref name=Hughes/> These mechanisms are only able to function due to the large-sized retinal image.<ref name="Martin1982"/> Thus, the primary nocturnal function in the vision of the owl is due to its large posterior nodal distance; retinal image brightness is only maximized to the owl within secondary neural functions.<ref name="Martin1982"/> These attributes of the owl cause its nocturnal eyesight to be far superior to that of its average prey.<ref name="Martin1982"/>