Nictitating membrane on Lewis's Woodpecker

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As noted in the post below, I took pics of this Lewis's Woodpecker today. In this pic, the woodpecker's nictitating membrane is over it's eye. The nictitating membrane is referred to as a bird's third eyelid. Bird's "blink" this nictitating membrane over their eye many times per minute and it apparently moistens the cornea.

High speed photography shows that woodpeckers close this nictitating membrane milliseconds before striking it their bills, thus protecting the eye from flying debris and also serving to hold the eyeball in place (to protect from the shock of the strike). Read more about the research on this and protection for their brains here

Double-click on the pic for a good close-up view of it's covered eye and also of it's tongue. SeEtta
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