Yellow-crowned Night Heron (Nyctanassa violacea) composite with blown eye |
American Oystercatcher (Haematopus palliatus) composite with blown eye |
I recently read about a congenital condition in humans called "iris colobomas" which is also found in other mammals and birds and have begun to wonder if that might not be the cause of the abnormal pupils I see in some species of birds instead of an injury to the eye.
Great Horned Owl (Bubo virginianus) composite with blown eye |
I've seen this condition in the species I have shown in my images and I've also seen it occur in Bald Eagles.
None of the birds I have photographed with blown eyes appear to have any difficulty seeing and it doesn't seem to limit their ability to stalk or hunt prey. The Yellow-crowned Night Heron in the image above stalked, captured and ate three Ghost Crabs while I observed and photographed it. American Oystercatchers probe for their prey and none of the birds with blown eye that I observed exhibited any more difficulty in locating food than the adults nearby that did not have this condition. The Great Horned Owl with the blown eye was a male and the pair had three chicks and I am almost certain he had no difficulties providing food for them.
I wonder how many other species exhibit "blown eyes" and what the cause is. Injury or Congenital Defect. I would love to read additional input on this topic so please feel free to comment.
Mia McPherson
OnTheWingPhotography.com
Very interesting, Mia. A little while back I did a painting of an American Oystercatcher based on a photo I took and noticed the dark flecks in its eye. When researching about it for my blog post (http://hipsterbirders.blogspot.com/2012/02/ode-to-oystercatcher.html), I came across a very cool article that may explain this phenomenon in Oystercatchers. Basically, the amount of flecks in the eye may determine the sex of the bird! Very cool, I think. Here is the link: http://onlinelibrary.wiley.com/doi/10.1111/j.1557-9263.2008.00167.x/abstract
ReplyDeleteFascinating post, Mia! I have never noticed "blown eye" in any of the birds I have seen before. I did not even know the condition existed until I read this post. Very interesting! All of your close-up photographs are excellent!
ReplyDeleteI haven't even heard of this condition before. Cutting edge Mia!
ReplyDelete...this is really interesting, Mia. I have seen it, but only rarely. I wondered if the bird was injured. I had not idea the condition had a name! Love the photos...and the info!
ReplyDeleteFirst of all, let me tell you your photos are truly fantastic!
ReplyDeleteYou have raised an interesting subject, and I would love to have the answer too!
Just maybe it could be due also by repeated contact with external (ie insecticides and so forth) or internal pollution (junk food: especially in humans!) and the new generations develop these kinds of defects, some visible some much less (infertility...). Then it might become congenital...
I would not think injury is the cause since too many birds are involved.
Only specialists could give a beginning of answer...!
Well done and a subject worth looking for true answers!
Cheers Tammy!
Thanks for all the comments on this post plus the kind words on my photography. Yesterday I was sent an image of a Great Egret from Melbourne, Australia that shows a blown eye too. I wonder how many species this can occur in.
ReplyDeleteHi Mia, great post and fantastic images as always. My guess is these are injuries. The pupil is actually an opening in the iris muscle. Interesting, horses eyes all have a bit of this look to them, for them it is normal (the first time i saw it in a horse my daughter was riding, i worriedly brought the trainer over and her reply, oh that's normal.)
ReplyDeleteEye eye.Beautiful images.
ReplyDeleteTruly fascinating as always, Mia, and fantastic images as well.
ReplyDelete