The guy behind the lens

Saturday, May 21, 2011

Thoughts on an Eagle's Eye.....

After having a great morning at the Blackland Prairie Raptor Center (BPRC) here in North Texas, I thought I'd share an image that I talked about with fellow photographers at the BPRC today.

In particular, we were discussing the fact that owls have small feathers on their eyelids and the discussion got around to the additional fact that many birds also posses a nictitating membrane which serves as a "middle" eyelid that allows the bird to blink without having to move the larger outer eyelid. The nictitating membrane allows most birds to blink but lets them to retain their vision as the membrane is usually semi-transparent. This membrane also moves differently from the usual eyelid as it closes horizontally over the eye rather than vertically. Occasionally when photographing birds, you may capture this nictitating membrane in mid blink and it creates a most interesting view as you see here. In this image I think the eagle looks like it could be a character out of the X - Men comics and movies.

Tawny eagle with nictitating membrane in place.

Here's an image of the same Tawny Eagle moments later....
Tawny EagleCenter for Birds of Prey, Awendaw, South Carolina

By the way, you do not posses a nictitating membrane, but the corner of your eye next to your nose does have the remnants of an vestigial nictitating membrane called the plica semilunaris. To see other interesting animal postings, visit Camera Critters!


11 comments:

TexWisGirl said...

nicely captured! straight out of SyFy Channel!

Anonymous said...

Wow - what glorious shots! The eyes look purple in the first one. Very cool indeed.

Kay L. Davies said...

Well, a vestigial one is better than none, right?
Wrong!
Great photos, John. I had no idea the nictitating membrane was blue, or horizontal, or so absolutely creepy. Sci fi for sure.
— K

Kay, Alberta, Canada
An Unfittie's Guide to Adventurous Travel

Unknown said...

I have seen that horizontal eyelid before but had no understanding of what it was. Lucky kids who have you for a science teacher.

Becca said...

I've never seen an eagle so close up...those eyes are insane!

eileeninmd said...

Wow, very cool closeups of the eagle.

Whimbrel Nature said...

Great post John! I've been planning an article on the nictitating membrane in diving ducks myself. Well written and photographed.

Unknown said...

Nicely shot John Beauty of a closeup

Anonymous said...

WOW! Not only do we get a chance to see some of the coolest pictures on the internet, but we get to learn a TON of new stuff! Great post, John, I really enjoyed this a lot!

Lisa said...

Wow. Stunning is what they are. Brilliant shots.

Unknown said...

That is quite a shot. Spooky looking! And thanks for commenting on my owl with the "windshield wiper" eyes on the Heard facebook site!

I think it was last year that I first met you when Mary (from the Heard Nature Photo Club) and I visited the Hagerman. You were so knowledgable and now I see why, after reading your bio. Thanks so much for sharing this blog with me. Can't wait to explore what you have written about!