Great Horned Owl

On the wild side—February, 2012

by Tina Mitchell

Who’s awake?  Me too!  Who’s awake?  Me too!  In the bleak midwinter, this series of muffled, slightly eerie hoots—all on one pitch—wafts through the darkness.  The sentinel taking attendance is the Great Horned Owl.  Measuring nearly 2 feet from head to tail, the Great Horned is the largest and most widespread owl in North America, found in every state of the continental U.S., all provinces of Canada, and down into Mexico.  Seen most commonly perched upright in trees or on power poles at dusk, this owl is heavily barred in brown and black.  Feather tufts (not horns at all, despite the name) on its large head give rise to its rather inaccurate, albeit catchy, common name.  Its beak looks rather small—although in reality it isn’t—because the base of the beak is covered with small feathers that grow in the direction of the tip of the beak.  (If you click on the link at the bottom of this article, you find a link to a photo of a Great Horned’s skull.  You can see the rather massive size of the beak there.)  Its enormous yellow eyes are so large that they cannot move in the owl’s head.  However, the owl can swivel its head more than 180 degrees to look in any direction.  Since Great Horneds hunt at night, locating prey by sound is vital—and this owl has the requisite acute hearing.  With a wide skull—nearly as wide as its body—its ears are set relatively far apart and offset from each other a bit, which allows the raptor to triangulate the location of the tiniest sounds even more accurately.  Its large and wickedly strong talons allow it to instantly snap the spine of even large prey.  As with many birds of prey, both males and females look the same, although females often are as much as 30% heavier.

This massive, powerful bird can live in a huge number of different habitats and in any climate except arctic and alpine regions.  Indeed, no other owl in North America makes use of so many diverse habitats.  Since they hunt from high perches, pretty much all they need are a few trees, some open areas for hunting, and an abundance of rodents and other mammals.  (In Colorado, they tend to favor areas with deciduous trees.)   First on the menu are rodents, rodents, rodents (e.g., mice, rats, voles)—followed by other nocturnal (active at night) and crepuscular (active at twilight) mammals such as skunks and rabbits.  Great Horneds have even been known to take on porcupines, although neither in that fight typically comes out very well.  Great Horneds will also capture bird as large as ducks or geese, snakes, lizards, and sometimes even insects.  As is true with most raptors, owls swallow their prey—bones, hair, tails, feet, feathers, teeth—whole.  An owl’s stomach has two parts—the proventriculus and the ventriculus—that separate and compress all of the indigestible parts of its food into a pellet, which it then egests or “casts”—fancy words for “throw up.” (Although the biology is a bit different, the process is not unlike a cat’s coughing up a hairball).

Great Horneds begin nesting very early in the year—typically in late winter.  They use an old stick nest built by a large bird such as a hawk, crow, or heron.  The female lays 2 – 3 eggs, often separated by several days.  The owlets hatch between 28 and 35 days after laying.  Only the female incubates the eggs and broods the hatchlings, relying on food brought by the male.  (One surefire way to find a Great Horned’s nest is to look for bulky stick nests in large leafless trees of winter.  Every now and then, you’ll spot what looks like a nest with ears.  That’ll be the female, hunkered down with just the top of her head showing, keeping the kids warm.)  Both parents provide food for as the nestlings grow.  The youngsters may climb around on nearby branches at 5 or 6 weeks; flight first occurs at 9 – 10 weeks.  The parents continue to the feed the fledglings for several months after they depart the nest.

Its scientific name—Bubo virginianus—comes from Latin for a horned owl (“bubo”) and  “pertaining to Virginia” (“Virginianus”), where the initial specimen originated.  The common name reflects its massive size (Great), the feather tufts resembling horns (Horned), and the Latin word “ululo,” meaning “to cry out” (Owl).

In some American Indian cultures, the owl embodies sinister or evil happenings.  Even in mainstream western culture, this creature often suggests mystery or trouble.  Who remembers the various references and appearances of Great Horned Owls in the 1990’s television series Twin Peaks?  (“The owls are not what they seem…”  Never a good omen there.)   In reality, though, the Great Horned Owl deserves our respect and deep appreciation.   Without the keen hunting skills of this mighty nocturnal raptor, the rodent population might now be running the world while we sleep.  Who’s awake, indeed…

To learn more about this fascinating denizen of the dark, see links to photos, and hear the many different calls of this bird, click here.