Monday, December 26, 2011

Have You Seen This Great White Hunter?

 In September 2010 I received an excited phone call from a friend’s daughter who lives in an undisclosed rural area of  Missouri.

On her way out of her neighborhood, with her children in the vehicle, she spotted what appeared to be a large white bird perched atop a road sign.  As she drew closer she realized, to her amazement, that it was an owl.  Neither my friend nor her daughter, are avid birders.  Beyond the fact that it must be an owl, she had no idea what she was seeing.  So, she called the only person she could think of who was really “into” birds—me.

When I picked up the phone I could tell my friend was REALLY excited!  She kept repeating that she was “….looking at an owl and it’s really, really, white!  What is it?”  The thought that it could be an albino fleetingly crossed my mind and was immediately discarded because I know how rare they are.  I began by asking the standard questions.  How big is it?  Does it have ear tufts (the feathers on the head that resemble little “horns”)?  What is its general body shape? 
A Great-horned Owl, the largest owl native to Missouri -- note the ear tufts 
Of course, to someone who is not accustomed to seeing owls in the wild at all, things like size and body shape are very subjective matters.  The closest we could get to an accurate description was the fact that there were no ear tufts and that it was “big”.  This ruled out two of our state’s most common native owl species—the Great Horned Owl (the largest) and the Screech Owl (our smallest native owl), both of which have ear tufts.
  An Eastern Screech Owl, the smallest owl native to Missouri -- note the ear tufts
That left the possibility that:
            a)  It could be a Snowy Owl that had wandered this far south (a very rare occurrence)
            b)  It could be an albino or leucistic Barred Owl (an incredibly rare occurrence)           
c)  It could be an extremely light colored Barn Owl that under dim lighting conditions could seem white (the most likely scenario) 
 A Snowy Owl - a rare and infrequent visitor from the North 
Since my friend had rarely seen owls in the wild I told her I was inclined to believe that the light colored Barn Owl was the most likely candidate, even though they are quite rare in eastern Missouri.  (What is it they always say about “assuming”)?   However, just to be sure I asked her to try to get a picture with her cell phone and email it to me.
An American Barn Owl - occasionally they can be much lighter and can appear white in dim light
After several days I emailed her to remind her about the photos, but when I heard no further from her I guessed that she was unable to get a photo and in the press of other things promptly forgot about the incident.

Last week (it is now December 2011) to my astonishment I received the following photo from my friend.  Her daughter had by now figured out how to email photos from her new cell phone and had sent her mother a number of photos.  When my friend saw the owl photo she immediately sent it along to me, since she knew I would be interested.
Believe it or not--this is a Barred Owl!
You guessed it!  It’s an albino Barred Owl!  So much for assumptions!  Now it was my turn to be excited!  I immediately called my friend, and this time it was my turn to babble.  I kept asking if they had any idea how rare this was!  Of course, this prompted a phone call from my friend’s daughter in which I was able to get more details about the encounter.
A normally colored and marked Barred Owl
Apparently after her original call to me in 2010 she took several photos of the owl, actually turning the car around in order to get a better shot.  The owl seemed undisturbed by the car, which indicates that it was accustomed to hunting near the roadside and considered vehicles to be just another part of its environment.  My friend stayed until it became too dark to take further photos.  She said they later saw the owl again on another occasion, but have not seen it lately.  It would be interesting to know if anyone else in rural areas of Missouri have seen this winged wonder.
Another view of our white Barred Owl showing no normal coloration in what should be his darker feathers
Just to give you an idea of how rare this is--following are some facts about albinism and leucism in birds that I found when researching the probabilities of seeing a Barred Owl of this color. 

            Leucistic -- Leucism is a condition characterized by reduced pigmentation in animals and humans. Unlike albinism, it is caused by a reduction in all types of skin pigment--not just melanin--resulting from defects in pigment cells during development. This results in either the entire surface (if all pigment cells fail to develop) or patches of body surface (if only a subset are defective) having a lack of cells capable of making pigment.  Leucistic individuals usually have normally colored eyes.

            Albinism -- Albinism in birds is rare, occurring to any extent in perhaps one in 1800 individuals (Terres 1980). (This number includes all bird species—the ratio for owls is even greater).  A bird that is albino (from the Latin albus, "white") has white feathers in place of colored ones on some portion of its body.  This condition is a genetically inherited trait resulting when each parent has the recessive gene for albinism.  A bird that is naturally white, such as a swan, goose, or egret, is not an albino, nor is a bird that has seasonally alternating white plumage (like the Ptarmigan, a Grouse-like game bird from the far North).

This would seem to be a very straightforward definition of the condition, but as in many cases within the scientific community, there are differences of opinion among the experts as to what constitutes albinism.  All seem to agree that there are four different degrees of albinism:

°            Partial albinism in which local areas of the bird’s body, such as certain feathers, are lacking the pigment melanin

°            Imperfect albinism in which the pigment is partially inhibited in the skin, eyes, or feathers, but is not absent from any of them (this produces a very pale, almost white version of their normal body pattern)

°            Incomplete albinism is the complete absence of pigment from the skin, eyes, or feathers, but not all three           

°            A completely albino bird is the most rare, lacking any pigment in its skin, eyes, and feathers. The eyes in this case are pink or red, because blood shows through in the absence of pigment in the irises. The beak, legs, and feet are very pale or white.  (Some authorities hold that albinism affects melanin pigments but not necessarily the carotenoid pigments (any of a class of yellow to red pigments). 

If the carotenoid theory is correct, then our white Barred Owl would probably qualify as a complete albino, whereas by the above definitions he could be an example of incomplete albinism (only a close examination of his skin could truly verify this).

In all my research I found only one reference to a total albino Barred Owl, and a very few recorded references to the other three types of albinistic Barred Owls. At any rate, this beautiful bird is most certainly a rarity.

Historically, the survival rate in the wild for albino animals is not good—due to poor eyesight in bright light caused by their condition, rejection by others of their species because of their color, and their lack of camouflage (whether they are a prey animal or a predator).  However, one theory presented in a study  of albino Great Grey Owls in Finland indicated that owls seemed less affected by these problems than most other birds.  This theory holds that these nocturnal predators’ hunting success depends largely on locating their prey by sound rather than by sight.  Thus, poor eyesight in bright light is not a disability to these nocturnal hunters.
Another view showing his yellow feet and beak--this would support the carotenoid theory
Is he still out there?  If you live in a rural area of Missouri have you seen this beautiful white hunter?  If so, we would love to hear from you via our “Comments” section on this blog. 

Submitted by Gay Schroer, World Bird Sanctuary Volunteer/Photographer

References: (Albinism in the Great Gray Owl (Strix nebulosa) and Other Owls) by Pentti Alaja and Heimo Mikkola1


FowelBall said...

That is amazing!

I was just Googling barred owls because I found one injured in the middle of a road and I'm trying to find a place to take it, but with the holidays I haven't had any luck getting a hold of anyone.

I'm near barnhart, mo. Any ideas where I can find someone to help today?

Photog said...

If you will call the World Bird Sanctuary wildlife hospital 636-861-1392 someone there will give you instructions as to where and how to bring in the owl. Unfortunately we do not have the manpower to come to you to pick up animals. If no answer at this number (they may be outside tending to patients) you can call 636-225-4390 and they will put you in touch with someone from the hospital.

Gretchen said...

Amazing! They got really good photos as well! What a find!

Anonymous said...

We have just discovered the presence of one just like this one in our back yard (Cedar Falls, IA)

Photog said...

Wow! What an incredible find--and in your own yard at that! Hope you got some photos. As rare as they are, you probably have had a once in a lifetime experience.