A Hawk with built-in skydiving goggles! (nictitating membrane)

I thought I knew a lot about animals, especially the ones I grew up with. Nope, not even close! Did you know that some hawks, if not all, have built-in goggles? I had no idea! I know that sharks do, to protect their eyes when they pounce on huge chunks of meat and bones. Since raptors, especially hawks and falcons, dive at such high speed, they probably need a little help to protect their eyes, much like skydivers wearing goggles. I have forgotten my goggles a few times during my skydiving days. Yups, it’s not pretty.
Anyway, this video turned out crisp as usual using 20mm pancake f1.7. It’s an amazing lens for a closeup.