Third Eyelid
Visitors to our osprey livecam may have noticed a clear film appearing over Rachel’s eye every so often. This film, a transparent fold of skin that sweeps sideways over the eye like a third eyelid, is known as the nictitating membrane. Its uses are manifold; it works as goggles to protect the eye during dives, and also helps shield Rachel’s and Steve’s eyes from the sharp beaks of their own chicks!
