Great Horned Owls (Don Moseman)

Owls: Custom-Made for Night Hunting

From Park E-ventures, July 2013

Recently, during a hike on one of northern California’s beautiful trails, I found a tail feather from a Great Horned Owl (Bubo virginianus). It was a long wing feather—mottled shades of white and brown and covered in fuzz, a signature of many owl species.

The feather was an interesting reminder of some of the adaptations that owls have for survival. Great-horned Owls are rapacious predators and span North America from coast to coast. Their ability to tolerate people and hunt everything from mice to other birds of prey make them a formidable predator.

Great Horned Owl Feather (Chris Briggs)

Owl feathers in particular are fascinating and serve many functions. They serve as insulation (think: down jacket), camouflage, and a means of stealth. The first two functions are common among many species of birds. Camouflage helps owls stay undetected from predators and potential prey—and limits harassment by other birds, which often see owls as a threat and will dive on them to drive them away. So if you hear jays and crows insistently calling from one place, it may be worth a look to see who they are harassing!

As most owls are nocturnal, sound is a very important aspect of their lives. Their excellent hearing allows them to track down and silently ambush prey. Owl feathers help them remain quiet. One adaptation is the comb-like leading edge of feathers in the wing. This allows the turbulence that comes off the wing—a cause of noisy flight—to be broken up. In addition, owl feathers are covered in a soft velvet-like structure that dampens sound. Finally, owl wings are large and have a lot of surface area relative to their body size. While this feature may make them slow, it also prevents them from having to flap as much—thus helping maintain their silence.

Another adaptation to sound is the owl’s facial disk, made up of stiff feathers that form a veritable “satellite dish” around each eye and direct sound to the ears. Owls can control this disk to focus on sounds at varying distances.

To help detect the origins of a sound, most owls have ears that are asymmetrically located in the skull. This means that, unlike humans with our symmetrical ears, owls are very good at locating sounds in three-dimensional space. In fact, Barn Owls can hunt in complete darkness, and Great Gray Owls can hunt voles and other small mammals that are covered by many inches of snow—by listening for their movements.

Great Horned Owl (Don Moseman)

Naturally, owl vision is also very good, but adapted towards darkness. They have large eyes to collect a lot of light. Their eyes are so big, in fact, that they have lost the muscles that move eyes around in their sockets (what allows us to look around without turning the head). But that loss is likely what led to the ability to turn their head 270 degrees in either direction—compared to a human’s ability to rotate only about 90 degrees in either direction.

Owls also have a tapetum lucidum behind each eye—a reflective surface that bounces light back toward the photosensitive cells in the eyes to give the cells a “second chance” to detect differences in light. This is what makes owl eyes “glow” at night, with even a small amount of light. The same effect can be seen with cats at night; cat eyes seem to glow as the light bounces off the tapetum lucidum and back out of the eye.

Owls certainly are not the wise creatures of the night often described in folklore. However, they are well-adapted to their niche. While they are no more specialized than any other bird, their adaptations to the quiet dark are interesting to think about when we are lucky enough to run across evidence that we have crossed their path—like a feather on the ground.

By Chris Briggs
Banding Program Manager
Golden Gate Raptor Observatory

Owl photos by Don Moseman. Feather photo by Chris Briggs.


Return to Park E-ventures archive or read more articles about related:

Topics: Birds

 

 

Comments

* * *
We're experiencing this alarming trend right here in Greensboro, North Carolina. For example, one of our local hospitals, the Moses Cone Health Center, finds that about 10% of ER cases are related to dental issues.. Wedding Limos 
Submitted by ali on January 25, 2015 
* * *
This ICC Earth Cup 2011 will likely be co-hosted by means of India, Sri Lanka in addition to Bangladesh; the settings in most of these countries are finalised. Orginally, Pakistan were being also co-hosts having some matches for being held as country. www.scorespro.com  
Submitted by www.scorespro.com on January 22, 2015 
* * *
I Appreciated What You Have Done here. I am Always searching for informative information like this. http://grand77.asia/asiapoker77/  
Submitted by Anonymous on January 18, 2015 
* * *
Great knowledge, do anyone mind merely reference back to it Arcane Legends hack  
Submitted by william on January 17, 2015 
* * *
That's awesome! I've been cat-and-mouse for that back forever! Thanks a lot for it! westwood new ec  
Submitted by westwood new ec on January 12, 2015 
* * *
It is really great to read about all the internship experiences directly from the students. They should encourage higher participation rate when the next internship program opens. bubblegum casting 
Submitted by Anonymous on January 11, 2015 
* * *
Their ability to tolerate people and hunt everything from mice to other birds of prey make them a formidable predator.bubblegum casting  
Submitted by Anonymous on January 10, 2015 
* * *
You made some clear points there. I did a search on the issue and found most people will agree with your website. Hair Loss Black Book 
Submitted by Sienna on January 10, 2015 
* * *
If you've been struggling accompanying how to research diy home security your best choice, this composition volition fanfare you four tolerant strides to writing consistently foremost excellence compositions. The primary gadgets you desire to focus on are the treatise theme, the rift paragraph, the total composition of the endeavor, further your composition text besides analysis. This piece too gives groups to part else expedients for endeavor writing.  
Submitted by britney on January 8, 2015 
* * *
I loved to acknowledge you for this websites! Bless for using. Fantastic websites! Click here for darts for women  
Submitted by Click here for darts for women on January 8, 2015 
* * *
I never see such a kind of social affair in the later past. An obligation of appreciation is in place with respect to giving it to us. comforter sets full  
Submitted by comforter sets full on January 7, 2015 
* * *
Thanks to a brilliant effort in publishing your Information. One can be more informative as this. clash of clan cheats  
Submitted by clash of clan cheats on January 7, 2015 
* * *
To help detect the origins of a sound, most owls have ears that are asymmetrically located in the skull. bubblegum casting  
Submitted by Anonymous on January 7, 2015 
* * *
There are so numerous wwwritingservice can write my paper immediately nowadays. My burden is that negative sum are actual. How do I assure that the essay utility I choose is sterling also negative a scam? I wouldn’t like to extravagance my loot for substandard process.  
Submitted by britney on January 6, 2015 
* * *
Goodness! this is an uplifting news. Without perusing these article you live on the moon. Much obliged man, it was an incredible help perusing your web journal. best engagement rings  
Submitted by best engagement rings on January 6, 2015 
* * *
Develop our own wisdom by our own hard work. Wisdom just cannot be acquired by magic.bosphorus cruise  
Submitted by Anonymous on January 6, 2015 
* * *
I am additionally constructing new locales the greater part of the time and getting great results by utilizing regular systems. Cooking Games  
Submitted by Cooking Games on January 6, 2015 
* * *
This is a greatly exquisitely created article. I'll make a point to bookmark it and come back to scrutinize a more prominent measure of your supportive understanding. hip hop costumes  
Submitted by hip hop costumes on January 5, 2015 
* * *
I concur with you I might want to bookmark the page so i can come here again to peruse you, as you have done a sublime job. play return man  
Submitted by play return man on January 5, 2015 
* * *
Thank you for admin, I have recently been searching for info about this topic for a month bubblegum casting  
Submitted by Anonymous on January 5, 2015 
* * *
Very informative and helpful. I was searching for this information but there are very limited resources. bubblegum casting  
Submitted by bubblegum casting on January 1, 2015 
* * *
You could have accomplished a terrific career. I'm self-confident they'll be benefited using this website. http://nutritionreviewers.com  
Submitted by Anonymous on December 16, 2014 
* * *
This is also a very good post which I really enjoyed reading. It is not everyday that I have the possibility to see something like this. agen asiapoker77  
Submitted by agen asiapoker77 on December 14, 2014 
* * *
What I have found from your site, it is really exceedingly content. Eminent post.nettikasinot  
Submitted by nettikasinot on December 8, 2014 
* * *
I would like to impart a greater amount of this great article which I discover great data from the article,i took in a considerable measure. best dating sites  
Submitted by best dating sites on December 8, 2014 
* * *
An extremely fascinating article much obliged concerning imparting it to every one of us. loans for people with bad credit and no bank account  
Submitted by loans for people with bad credit and no bank account on December 4, 2014 
* * *
Took me time to read all the comments, but I really enjoyed the article. It proved to be Very helpful to me and I am sure to all the commenters dentist tequesta here! It’s always nice when you can not only be informed, but also entertained! 
Submitted by jackdon on December 2, 2014 
* * *
this web journal is realy admired its realy great and this sight give extraordinary data i realy need to utilize this site will u. agen taruhan bola  
Submitted by agen taruhan bola on November 29, 2014 
* * *
Great article! Only one slight typo in the first two sentences. You mentioned finding a tail feather in the first sentence and that is was a long wing feather in the second sentence. 
Submitted by Teresa on June 29, 2013 

 

Leave a comment

Name
Comment
Enter this word:


Browse Park E-ventures by Topic

Topic
Program 
 

Browse Park E-ventures by Date