Reflex blinking

Corneal reflex in a barking owl

A caged barking owl (Ninox connivens) was observed sitting on a perch. Each time it turned its head to the front, a twig brushed the left cornea. For some reason he did not change its position but allowed this to happen repeatedly. Of interest to a human neurologist was that only the left upper eyelid closed when the left cornea was touched (see Video 1 and Figure 1). Unlike humans, there was no consensual corneal reflex. Well, almost no consensual reflex for as you can see, at 200ms after the blink has started, the right nictitating membrane has lowered minimally.