There are a few interesting things going on in this video: gular fluttering, nictitating membranes, and head bobbing. Owls and other birds use gular fluttering to stay cool when the temps are high. Owls nictitating membranes (essentially a second eyelid) help protect their eyes when attacking prey. Lastly, head bobbing (motion parallax) helps owls triangulate their sight on a given subject since their eyes are fixed in their skull and cannot move on their own.
My Earth 