An Owls 3rd Eyelid
Today we caught two Northern Saw-whet Owls with wonderful WNW winds. While Photographing this owl, we happen to notice that with each picture it would use its 3rd eyelid (as if to protect itself). After looking in a few of my Ornithology Manuals – I finally learned that this eyelid is called the Nictitating membrane!! After a quick google search: answers.com I found this about the eyelid: nic·ti·tat·ing membrane (nĭk’tĭ-tā’tĭng) also nic·tat·ing membrane (nĭk’tā’tĭng) n. – A transparent inner eyelid in birds, reptiles, and some mammals that closes to protect and moisten the eye. Also called third eyelid.
FYI: Nexrad Radar shows a very strong movement of birds taking off just after sunset. Click link to see the Clip.