Which species of bird lives and nests in more counties in the
continental U.S. than all others? The answer, the great-horned
owl, comes as a surprise to many people. These creatures of the
night are capable of nesting and surviving where many other owls
cannot. Where there is a lack of trees, they will nest upon the
ground. Their primary requirement is live, available prey
species.
These largest of all nesting owls in our country are most
active during darkness, their "world of night." Not
only is the darkness in their favor as they hunt for food, they
also possess a marvelous array of physiological and anatomical
adaptations that help them to hunt at night.
The leading edges of their long wide wings are very soft and
serrated, thereby providing these awesome birds with nearly
silent flight. Their thick layer of soft body feathers also
helps to mute flight sounds as well as provide excellent
insulation in sub-zero weather.
This owl’s ears, as well as other owl species, are
asymmetrically shaped and placed on the sides of its head. One
of the ears enables the great-horned to localize sounds in the
vertical position, how low or high above the ground the sound of
their prey is. The other ear reads the horizontal location,
exactly from where to the left or right of the bird the strange
squeaking or rustling sounds are coming. Finally the distance
between the two ears provides the owl with triangulation and an
amazingly accurate gauge of distance, how far away the mouse or
other prey is.
We are fortunate to be living in excellent great-horned owl
habitat. Their nighttime and pre-dawn singing has especially
intrigued us ever since we moved into our Houby Hill woods home.
Less than a mile to our east lies the thickly-wooded Hibbards
Creek valley that also provides horned owls of the area with
excellent hunting.
This past early winter, upon hearing the singing of one of
these large owls east of our house, I took out two of my favorite
ocarinas, both in the key of C, to check on the pitch of our
owl-friend’s vocalizations. One of the ocarinas (which by the
way means "little goose" in Italian) is made of terra
cotta and is my lowest in pitch. The highest note it plays is
middle C (on the piano). I had naturally assumed that this large
owl’s voice surely would place it in the "bass section"
of the owl chorus. Much to my surprise the majority of its
rather monotone singing was on or very near middle C, and not as
low as I had envisioned.
Charlotte and I were royally treated one early evening this
past January to the pair-bond singing of two great-horned owls.
In light of the fact that the male is smaller than the female,
nevertheless his voice is lower, stronger and mellower. Her song
invariably is softer and usually three or four half-tones higher
than that of the male. Occasionally, during their beautiful
concert, her song would immediately follow but wouldn’t begin
until his was completely finished – something like "who
WHOOO who who." At other times she would chime in before he
had completed his "aria." And once in a while they
would sing a nearly perfect duet, even though it wasn’t in the
best of harmony.
Like a foghorn, the songs of the owls are sound-beacons in the
night. Not only are they used during courtship, they also
provide the birds with territorial assertion – "This is my
property, please keep your distance!"
A commonly asked question regards the larger size of the
female owl. Consider the incredibly sharp, weapon-like talons
these birds have. Courtship could conceivably get to be quite
savage and, the thought is that, should the male be larger than
the female, he might badly injure of even kill her. It is not
uncommon for a large female, paired with a small male, to be a
pound heavier, seven inches longer, and have a one-foot-longer
wingspan.
You’ve heard of "eating crow?" Well, great-horned
owls really do! Little wonder the crows mob and pester the
daylights out of an owl by day, but eventually the great-horned
gets revenge by raiding their roosts at night, killing and eating
some of the crows. It’s quite easy to pinpoint the location of a
great-horned owl during the day simply by hearing the raucous,
frenzied chorus of mobbing crows. Fortunately once they begin
their nesting their interest in the big owls will suddenly
subside.
The female great-horned will lay usually two or three eggs,
sometimes well before the end of February. The eggs are
incubated for 28-30 days before the tiny owlets, the size of baby
chicks, are hatched, covered with a soft, thick, gray-white coat
of down, but with their eyes closed. The owlets will attain a
third of their ultimate size in 14 days, half-size in 21 days,
and be nearly of full-grown by the end of four weeks.
The young will be flying well at their twelfth week but will
be a half-year old before their talons have become fully grown
and they are capable of skilled flight and of hunting their own
food. Little wonder the nesting of these birds begins so early
in the year.
Ernest Thompson Seton ranked these "flying tigers"
among the most pronounced and savage of all birds of prey. It’s
quite wonderful to realize that so many counties in our country
are still wild enough to support these magnificent creatures!
Good thing they are largely active at night, a time when most
humans are safely locked in their little "boxes!"
A great-horned owlet, five to six weeks old and
well camouflaged, peers out at its world.
Also see:
This column appeared in the Door County Advocate
on 03/16/2001.
© Copyright 2001 Roy Lukes. All rights reserved.
