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DISTRIBUTION
Great Horned Owls (Bubos virginianus)
are found throughout North America from the northern treeline
and south to Central and South America. They are resident
year-round, however, birds living in the northern part of
the species' range may migrate south.
Great Horned Owls have adapted to
many different places and climates. They occur in habitats
from dense forests, deserts and plains to city parks. They
have been known to inhabit the same area as the diurnal (active
during the day) red-tailed hawk.
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Size: Length 18-25"; wingspan 36-60"; weight
32-63½ oz |
DESCRIPTION
Great Horned Owls can vary in colour from
a reddish brown to a grey or black and white. The underside
is a light grey with dark bars and a white band of feathers
on the upper breast. They have large, staring yellow-orange
eyes, bordered in most races by an orange-buff facial disc.
The large feet are feathered to the ends of the toes, and
the immature birds resemble the adults. Females are 10 to
20% larger than males.. |
| The name,
Great Horned Owl, is derived from tufts of feathers that appear
to be "horns" which are sometimes referred to as "ear tufts"
but have nothing to do with hearing at all. |
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DIET
Great Horned Owls hunt by perching on snags and
poles and watching for prey, or by gliding slowly above the ground.
From high perches they dive down to the ground with wings folded,
before snatching prey. Prey are usually killed instantly when grasped
by its large talons. A Great Horned Owl may take prey 2 to 3 times
heavier than itself. They also hunt by walking on the ground to
capture small prey or wading into water to snatch frogs and fish.
They have been known to walk into chicken coops to take domestic
fowl. Rodents and small rabbits can be swallowed whole while larger
prey are carried off and ripped apart at feeding perches or at the
nest. Birds are often plucked first, and legs and wing tips discarded.
An extremely wide range of prey species (at least
253 identified) are captured, but rabbits and hares are its preferred
prey. Mammalian prey includes all coexisting rodents, squirrels,
mink, skunks, raccoons, armadillos, porcupines, domestic cats and
dogs, shrews, moles, muskrats, and bats. Bird prey includes all
other Owls (except Snowy Owl), grouse, woodpeckers, crows, turkeys,
pigeons, Red-tailed Hawks, bitterns, Great Blue Heron, ducks, swans,
gulls, etc. Reptiles include snakes, turtles, lizards, and young
alligators. Amphibians include frogs, toads, and salamanders. Other
foods include fish, large insects, scorpions, centipedes, crayfish,
worms, spiders, and road killed animals. |
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A Great Horned Owl perches in a tree at
right. Notice camouflage coloring. Above, a young Great Horned
owlet. Notice the small ear tufts. |
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LIFE CYCLE/SOCIAL BEHAVIOR
The Great Horned Owl spends the majority of its
time hunting. The owl can see during the day, but has even better
vision at night. The silent flight of this owl can be attributed
to its loose, soft feathers. These two factors, and the fact that
its prey is most active at night make it most advantageous for the
Great Horned Owl to hunt at night.
When there are young in its nest, the Great Horned
Owl is known to be very hostile. The owl has been observed flying
near intruders snapping its bill and hooting. Overall, the Great
Horned Owl is a powerful, swift, and graceful bird of prey. |
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Young Great Horned Owl |
REPRODUCTION
Nesting season is in January or February
when the males and females hoot to each other. When close
they bow to each other, with drooped wings. Mutual bill rubbing
and preening also occurs. They do not build a nest of their
own but utilise the nests of other birds such as the hawk,
crow and heron. They may also use squirrel nests, hollows
in trees, rocky caves, clumps of witches broom, abandoned
buildings, or on artificial platforms. They are extremely
aggressive when defending the nest and will continue to attack
until the intruder is killed or driven off. |
Female protecting nest |
| Normally, two to four eggs are laid
and incubated by the female only for 26-35 days. Young start
roaming from the nest onto nearby branches at 6 to 7 weeks,
when they are called "branchers", but cannot fly well until
9 to 10 weeks old. They are fed for another few weeks as they
are slowly weaned. Families remain loosely associated during
summer before young disperse in the autumn. Adults tend to
remain near their breeding areas year-round while juveniles
disperse widely, over 250 km (150 miles) in the autumn. Territories
are maintained by the same pair for as many as 8 consecutive
years. |
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COMMUNICATION
Great Horned Owls
have a large repertoire of sounds, ranging from deep booming hoots
to shrill shrieks. The male's resonant territorial call "hoo-hoo
hoooooo hoo-hoo" can be heard over several miles during a still
night. Both sexes hoot, but males have a lower-pitched voice than
females. They give a growling "krrooo-oo" or screaming note when
attacking intruders. Other sounds include a "whaaa whaaaaaa-a-a-aarrk"
from disturbed birds, a catlike "MEEE-OWww", barks, hair-raising
shrieks, coos, and beak snapping. Some calls are ventriloquial.
Most calling occurs from dusk to about midnight and then again just
before dawn.
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INTERESTING FACTS
1. Great Horned Owls will "cache," or store,
food. In winter, if the stored prey is frozen, they will thaw their
dinner by incubating it.
2. Captive Great Horned Owls have been known
to live 29 to 38 years, and wild Owls up to 13 years. Most mortality
is related to man - shootings, traps, road kills and electrocutions.
The only natural enemies are other Great Horned Owls and, occasionally,
Northern Goshawks during disputes over nest sites.
3. The young Great Horned Owl fledglings
leave the nest before they are able to fly, walking around on the
forest floor, sometimes for days. The parents continue to protect
and feed these adolescents until flight is attained.
4. The Great Horned Owl controls harmful rat
and mice populations throughout the United States.
5. Other names for this Owl include: Big Hoot
Owl, Cat Owl, Virginia Owl, and Virginia Horned Owl.
6. The Great Horned Owl has also been called
the "Tiger of the Air ". The tiger comparison applies well to the
Owl's manner of hunting,.for the sweep of his great wings in the
silent air is as noiseless as the tread of the big cat's padded
feet upon the soft earth. Through the woods and over the meadows,
the Great Horned Owl glides as silently as a shadow, and to the
unwatchful rabbit or the slumbering Partridge that shadow is the
possible precursor of a sudden death. |
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