Blog reader John
Foehner recently submitted the following comment on our blog article "Barn Owl Fun Facts: Part 1": “Great info! Barn owls
are one of my favorite birds. Here's a question for you that I've never had
answered... Barn owls are beautiful birds with an awesome design on their light
golden/tan/white feathers. Why? It doesn't seem to be used for camouflage and a
largely nocturnal bird wouldn't seem to need special coloring for ID or
courting? Although most birds are pretty in one way or another, I can't figure
out why barn owls look the way they do. So, why? “
Just a few of the color pattern variations here at WBS--left to right are Moonshine, Farnsworth, Dawn & Abby
I’ll have to admit
that even though I have taken hundreds of photos of the Barn Owls at WBS, I had
simply taken their beautiful feather patterns for granted as just another part
of what makes this species so fascinating.
John’s question sent
me into a fury of researching the whys and wherefores of Barn Owl
coloration.
There are
approximately 35-40 known subspecies of Barn Owls--the exact number is
arguable, depending on which expert source you are reading at the moment. Since Barn Owls are found on every
continent except Antarctica (and some islands), their territories sometimes
overlap resulting in some sub-species that interbreed—thus the discrepancy in
the number of listed sub-species.
Our sweet little Tobin, a European Barn Owl, was so light colored that when viewed from below he might easily have been mistaken for a Snowy Owl
Among the multitude of
sub-species there is a wide variety of differences in the coloration and
shading of individuals—some being so light when viewed from below that they are
sometimes mistaken for a Snowy Owl, and others having a buffy or beige coloring
on the underside.
Note how well this Barn Owl blends in when seen from above...even though this is not a natural environment
Even though Barn Owls are largely nocturnal, they are also crepuscular (active at dusk and dawn). Hence the need for camouflage. When viewed from
above—they are universally a blend of dark grey/brown backs and wings. This difference in coloration (light
underside and dark backs and wings) is an example of “counter shading”—an
adaptation used for concealment.
When in flight it allows them to take full advantage of the interplay
between light and dark—enabling them to “disappear” as they change direction in
flight, thus avoiding other predators who might be looking for a Barn Owl
snack.
As a general rule, the white/light colored feathers on the
breast are spotted—in some individuals the spotting is so light that from a
short distance the breast appears to be solid white. However, in other individuals the breast is heavily
spotted. The females are more
heavily spotted than the males.
One of the most interesting theories that came to light in
my research is that the spotting may indicate the quality of the female. One study found that the more heavily
spotted females get fewer parasitic flies and may be more resistant to
parasites and diseases. Also, in
another experiment when some females’ spots were removed their mates fed the
nestlings less often than for heavily spotted females. As a general rule, most of my research
sources concurred that it appears that heavily spotted females are healthier.
Another study showed that female Barn Owls with larger spots
have a greater success in mating, whereas large dark spots on the breast
appears to hurt male Barn Owls’ reproductive success.
And, finally, another study indicated that nestling Barn
Owls frequently feed their siblings.
This behavior predominates in individuals displaying a female-like
plumage trait (spots).
To see some of these color variations when visiting the
World Bird Sanctuary be sure to check out the color patterns on the various
Barn Owls on display.
Submitted by Gay Schroer, World Bird Sanctuary
Volunteer/Photographer
1 comment:
Thanks Gay, lots of good information. It does make a lot of sense. I also wonder if the female being more spotted are more camouflaged when on her nest to better hide/protect the nest and the eggs/owlets. Whereas, the male, with the more brighter white breast stands out more to say this is MY territory look at ME Go Away! A male that blends into the background is not much of a deterrent.
I agree with you, Barn Owls are beautiful for what ever reason they are!!
Haha new word for the day crepuscular -active at dusk and dawn!
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