The more bird photographs I take, especially using the 12 frames per second shutter on my Nikon D5, the more nictatating membranes I see on the eyes of birds I photograph. Nictatating membranes are like a third eyelid that is somewhat transparent and moves across the bird’s eye quickly. I noticed that many of the sandhill crane photographs I got lacked sparkle in the eye until I realized the membrane was covering the eye. In this photograph, the membrane is only partially covering the eye making it more visible.
Ohhhhhh! Love this!