Eyes and Eyesight |
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| As predators, raptors need keen sight for
spotting and catching their prey. Every bird has eyes which are relatively large; the
larger the eye, the greater number of light-sensitive cells it can hold, and the better
the vision. That is why owls in relation to the size of their head have very big eyes.
Owls cannot move their eyes from side to side, instead they have to move their heads. The
size of their eyes in comparison to their head leaves no space for muscles so their eyes
are fixed into the eyeball socket. To compensate for this, the muscles are used to make
their heads move in a 180 degrees angle which makes the owl appear as if it can move its
head right round. It is a popular belief that Owls can see in total darkness, but this is not the case, as all owls need some light such as moonlight to see clearly. However Owls can see in light up to 100 times poorer than the minimum needed by people. Birds of Prey have eyes more to the front of their heads than most other birds. The best position for keeping and intended victim in view. This also allows them to judge distance accurately, for the visual field of the two-eye everlap, giving an area of binocular, three-dimensional vision. Birds of prey have also what is called a third eyelid, or nictating membrane that cleans and protects the eye. It is transparent so the bird’s vision is never completely lost.
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