Bird Facts: The Great Horned Owl

(Photo: My own capture of a Great Horned Owl. Taken in Sonoma County, Northern California.)

THE GREAT HORNED OWL

Possessed of extremely keen visual and auditory senses, the Great Horned Owl (Bubo virginianus) is an incredibly efficient nocturnal predator. It has one of the widest geographical distributions of any non-migratory bird as there are approximately a dozen sub-species of varying colorings and sizes (most named for the regions they occupy, e.g., "California", "Rocky Mountain", "Desert", "South American", etc.) residing from above the Arctic Circle in North America down to the southern portion of South America.

With a body that can attain over two feet in length and a wingspan of up to five feet across, the Great Horned Owl is one of the Western Hemisphere's largest raptor birds. Named for the pointed tufts of feathers -- called "plumicorns" -- on either side of the top of its head, the Great Horned Owl's "ears" or "horns" give it a distinctly cat-like appearance, making positive identification a simple matter even for the most inexperienced of bird watchers.

The Great Horned Owl is, in fact, the largest "eared" owl in North America and, while hunting, utilizes its remarkable powers of hearing at least as much its legendary night-vision. Because one ear is slightly higher and positioned at a slightly different angle on the head than the other, it is able to use a kind of "sound triangulation" process to judge the location of its prey with amazing accuracy.

The species can also be identified by its unique vocalizations.

The call of the Great Horned Owl consists of five (rarely four) distinct hoots: "Hoo-hoo-hoo HOO hoo!" and mated pairs can often be heard answering each other, back and forth, from separate perches that are some distance apart. As is the case with many raptor birds, female Great Horned Owls are on the average about one-third larger than their male counterparts -- oddly, however, the deeper sounding call is usually made by the male rather than by his larger female companion.

For centuries, humans have admired the Great Horned Owl's powerful sense of sight; especially its ability to see small objects at long distances in very low ambient-light conditions. Their eyes are nearly as large as our own in a body roughly one-third the size. This allows a huge amount of the available light (no matter how small of an amount that might be) to enter, along with the rest of the visual data, through the eyes to be processed in the ocular center of the brain. Additionally, the Great Horned Owl shares other raptors birds' (such as eagles' and hawks') "binocular-like" vision for seeing long distances.

The Great Horned Owl has another physical feature which adds to its reputation as a "super predator": Fringed flight feathers that act as "silencers" in flight. Even prey with keen hearing is at a distinct disadvantage in its fight for survival against the Great Horned Owl because, despite its large size, this owl is virtually noiseless in flight. More than one person has told a tale of taking a walk in the late night silence only to find themselves suddenly engulfed in a flurry of feathers in a near-collision with a Great Horned Owl single-mindedly pursuing its prey!

The other lethal weapons in the Great Horned Owl's arsenal take the form of its exceptionally powerful talons that are capable of generating a reported 500 lbs. per square inch in crushing power. (By way of comparison, human males average about 60.)

The Great Horned Owl's prey consists mostly of rodents like mice and rats, squirrels, rabbits, moles and the like; other larger animals like raccoons, woodchucks, foxes and even porcupines; bats and birds -- including other owls (it is the primary predatory threat to Barred Owls); however, cold-blooded creatures such as snakes, lizards, frogs, fish or large insects make up only a very small percentage of their diet.

Prey is usually swallowed whole with indigestible parts (like fur and teeth) regurgitated later.

The Great Horned Owl is the only predator that regularly feasts on skunk and has even been known to snatch up small domestic dogs and cats. It is often the victim of "mobbing" (group attacks) by large flocks of American crows, probably owing to its menacing nature.

Great Horned Owls are among the first birds in the year to lay their eggs (January/February) in small clutches of two or (rarely) more eggs. Both the male and female take turns incubating the eggs and it takes about six months for fledglings to gain sufficient maturity to leave the nest. Young Great Horned Owls may wander for a year or two until they find a mate. They have also been known to linger near the parents' nest until the parents produce another clutch of offspring (an additional six months) but, in any case, most Great Horned Owls spend their entire lives no further than just a few miles away from the place where they were hatched.

Probably due to their nocturnal habits, owls were generally perceived as negative omens in the folklore and mythologies of most of the indigenous American tribes. They were considered to be the allies (and sometimes servants) of medicine men or witches by the Pawnee, Cherokee, Hopi, Choctaw, Alabama, Ojibwa and others -- some of whom credited them with the ability to shape-shift from witches into owls and back again. In fact, the Cherokee words for "witch" and "owl" are the same: "Skili".

The Pima, Lakota, Omaha, Fox, Creek and some tribes of the Sierra Nevada also held the belief that the soul of the departed entered into an owl after death in order for it to be flown to the afterlife. Therefore, most of the previously-mentioned tribes considered an actual visitation by (especially) a Great Horned Owl to be an omen of future misfortune or death.

Undeserved though this dark reputation of the owl may be, many human beings, even today, have misgivings associated with this splendid predator. In the poem, The Owl and the Farmer, by John Gay, perhaps we may have stumbled upon the owl's indignant rebuttal:

Reason in man is mere pretense:
How weak, how shallow is his sense!
To treat with scorn the bird of night,
Declares his folly -- or his spite...

 Sources:

http://en.wikipedia.org/wiki/Great_horned_owl

http://www.oregonzoo.org/Cards/BirdsOfPrey/greathornedowl.htm

http://www.allaboutbirds.org/guide/great_horned_owl/id

http://hinhan.blogspot.com/2008/03/owl-lore-placeholder.html

http://www.chieftain.com/articles/2009/02/15/life/local/doc499774c877f84364050923.txt

http://www.experiencefestival.com/a/owl%20-%20myth%20and%20lore/id/597095

http://scaredowlwisdom.com/myth.html

http://www.maskmaker.com/samples/owl_horned.html

http://www.poemhunter.com

(Author's Note: The above article was written for and first appeared on Helium.com, June, 2009.)