An online resource based on the award-winning nature guide

Owls & Humans Share Trait

barred owl 194Birds have three eyelids – an upper eyelid, lower eyelid and a third semitransparent membrane called a nictitating membrane that sweeps across the eye much like a windshield wiper. This membrane keeps their eyes moist, and protects their corneas from being scratched.

In most birds, including owls, the upper and lower eyelids are used to close the eyes when sleeping, and the nictitating membrane is used for blinking. Humans close their eyes mainly by lowering the upper eyelid, where most birds do so by raising the lower lid. Owls (and a few other birds such as parrots, toucans, wrens and ostriches) are more human-like in that their upper lids are usually lowered to close their eyes. Owls also usually close their eyes, partly or entirely, when capturing and transferring prey, scratching their face, preening another owl and copulating. (Note the rows of feathers on this barred owl’s upper eyelids.)

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One response

  1. Laura Andrews

    Mary, I’ve been watching the great horned owls at the link you sent end of January. The two eggs hatched, the owlets have grown, but are still in the nest. The older one has branched, but the younger hasn’t. it’s been amazing to watch them develop. AND, they can blink one eye at a time! We can’t. (Winking doesn’t count!) Thanks for sending that – it’s been a blessing during this record winter. Laura

    March 24, 2015 at 7:09 am

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