Posted by David Sparks on June 11, 2009 at 11:59 AM
The 3 photos show the nictitating membrane of a Black-crowned Night Heron covering about one-half (this photo), almost all, and all of the eye.
More information about the membrane and it's function can be found here http://en.wikipedia.org/wiki/Nictitating_membrane
Posted by David Sparks on June 11, 2009 at 12:00 PM
nictitating membrane covering almost all of the eye
Posted by David Sparks on June 11, 2009 at 12:01 PM
nictitating membrane covering all of the eye
Posted by Ron Bielefeld on June 11, 2009 at 12:39 PM
Cool. Don't you wish we had build in saftey and swimming goggles. Ron
Pretty neat Dave. My other hobby is carpentry (furniture building) and a fully functional nictitating membrane would have saved me much discomfort from sawdust in my eyes when I've foolishly neglected to use safety glasses.
Discussion
5 repliesMore information about the membrane and it's function can be found here
http://en.wikipedia.org/wiki/Nictitating_membrane