With
its long, earlike tufts, intimidating yellow-eyed stare, and deep
hooting voice, the Great Horned Owl is the quintessential owl of
storybooks. This powerful predator can take down birds and mammals
even larger than itself, but it also dines on daintier fare such
as tiny scorpions, mice, and frogs. Its one of the most common
owls in North America, equally at home in deserts, wetlands, forests,
grasslands, backyards, cities, and almost any other semi-open habitat
between the Arctic and the tropics.
At a Glance
Habitat
|
Food
|
Nesting
|
Behavior
|
Conservation
|
|
|
|
|
|
Open Woodland
|
Mammals
|
Tree
|
Aerial Dive
|
Least Concern
|
Measurements
Both Sexes
Length
18.124.8
in
4663
cm
Wingspan
39.857.1
in
101145
cm
Weight
32.188.2
oz
9102500
g
Relative Size
Slightly larger than a
Red-tailed Hawk.
Other Names
|
Cool Facts
- Great Horned Owls are fierce predators that can take large prey,
including raptors such as Ospreys, Peregrine Falcons, Prairie
Falcons, and other owls. They also eat much smaller items such
as rodents, frogs, and scorpions.
- When clenched, a Great Horned Owls strong talons require
a force of 28 pounds to open. The owls use this deadly grip to
sever the spine of large prey.
- If you hear an agitated group of cawing American Crows, they
may be mobbing a Great Horned Owl. Crows may gather from near
and far and harass the owl for hours. The crows have good reason,
because the Great Horned Owl is their most dangerous predator.
- Even though the female Great Horned Owl is larger than her mate,
the male has a larger voice box and a deeper voice. Pairs often
call together, with audible differences in pitch.
Great Horned Owls are covered in extremely soft feathers that
insulate them against the cold winter weather and help them fly
very quietly in pursuit of prey. Their short, wide wings allow
them to maneuver among the trees of the forest.
- Great Horned Owls have large eyes, pupils that open widely in
the dark, and retinas containing many rod cells for excellent
night vision. Their eyes dont move in their sockets, but
they can swivel their heads more than 180 degrees to look in any
direction. They also have sensitive hearing, thanks in part to
facial disc feathers that direct sound waves to their ears.
- The oldest Great Horned Owl on record was at least 28 years
old when it was found in Ohio in 2005.
|
Great Horned Owl
Adult
Large, heavy-bodied owl with noticeable ear tufts
Glowing yellow or orange eyes on tawny brown facial disc
Densely barred underparts
Gray, brown, and black camouflage pattern on upperparts
© Anne Elliot, AB, Calgary, September 2009 |
Habitat
|
|
Open Woodland
|
Found all across North America up to the northern tree line,
Great Horned Owls usually gravitate toward secondary-growth woodlands,
swamps, orchards, and agricultural areas, but they are found in
a wide variety of deciduous, coniferous or mixed forests. In some
areas, such as the southern Appalachians, they prefer old-growth
stands. Their home range usually includes some open habitatsuch
as fields, wetlands, pastures, or croplandsas well as forest.
In deserts, they may use cliffs or juniper for nesting. Great Horned
Owls are also fairly common in wooded parks, suburban area, and
even cities.
Food
|
|
Mammals
|
Great Horned Owls have the most diverse diet of all North American
raptors. Their prey range in size from tiny rodents and scorpions
to hares, skunks, geese, and raptors. They eat mostly mammals and
birdsespecially rabbits, hares, mice, and American Coots,
but also many other species including voles, moles, shrews, rats,
gophers, chipmunks, squirrels, woodchucks, marmots, prairie dogs,
bats, skunks, house cats, porcupines, ducks, loons, mergansers,
grebes, rails, owls, hawks, crows, ravens, doves, and starlings.
They supplement their diet with reptiles, insects, fish, invertebrates,
and sometimes carrion. Although they are usually nocturnal hunters,
Great Horned Owls sometimes hunt in broad daylight. After spotting
their prey from a perch, they pursue it on the wing over woodland
edges, meadows, wetlands, open water, or other habitats. They may
walk along the ground to stalk small prey around bushes or other
obstacles.
Nesting Facts
Clutch Size
14 eggs
Number of Broods
1 broods
Egg Length
2.12.2
in
5.35.6
cm
Egg Width
1.81.9
in
4.54.7
cm
Incubation Period
2629 days
Nestling Period
3037 days
Egg Description
Dull white and
nearly spherical, with
a rough surface.
Condition at Hatching
Helpless, with
closed eyes, pink
skin, and white down on upperparts. |
Nesting
Nest Description
Nests often consist of sticks and vary widely in size, depending
on which species originally built the nest (usually Red-tailed Hawks,
other hawk species, crows, ravens, herons, or squirrels). Great
Horned Owls may line the nest with shreds of bark, leaves, downy
feathers plucked from their own breast, fur or feathers from prey,
or trampled pellets. In some areas they add no lining at all. Nests
deteriorate over the course of the breeding season, and are seldom
reused in later years.
Great Horned Owls typically nest in trees such as cottonwood, juniper,
beech, pine, and others. They usually adopt a nest that was built
by another species, but they also use cavities in live trees, dead
snags, deserted buildings, cliff ledges, and human-made platforms.
In the Yukon they nest in white spruces with witches
brooms, which are clumps of dense foliage caused by a fungus.
They occasionally nest on the ground. Pairs may roost together near
the future nest site for several months before laying eggs.
Great Horned Owls roost in trees, snags, thick brush, cavities,
ledges, and human-made structures. They are active mostly during
the nightespecially at dusk and before dawn. When food supplies
are low they may begin hunting in the evening and continue into
the early morning; in winter they may hunt during daylight hours.
Mated pairs are monogamous and defend their territories with vigorous
hooting, especially in the winter before egg-laying and in the fall
when their young leave the area. Great Horned Owls respond to intruders
and other threats with bill-clapping, hisses, screams, and guttural
noises, eventually spreading their wings and striking with their
feet if the threat escalates. They may kill other members of their
own species. Crows, ravens, songbirds, and raptors often harass
Great Horned Owls with loud, incessant calls and by dive-bombing,
chasing, and even pecking them. Unattended eggs and nestlings may
fall prey to foxes, coyotes, raccoons, lynx, raptors, crows, and
ravens. Both members of a pair may stay within the territory outside
of the breeding season, but they roost separately.
|
Great Horned Owl
Adult with Juvenile
Adult large and bulky with obvious ear tufts
Adult has heavily barred underparts
Juvenile mostly covered in down, but with large, yellow eyes
like adult
Tawny brown facial disc on both
© Donald Thompson, FL, Highland City , March 2010 |
Conservation
status via IUCN
|
|
Least Concern
|
Great Horned Owls are common and widespread throughout much of
the Americas. According to the North American Breeding Bird Survey,
between 1966 and 2010 their populations were stable in the U.S.
but declined in Canada, resulting in an overall population decline
just under 1 percent per year (resulting in a cumulative loss of
30 percent). Partners in Flight estimates the global breeding population
at 6 million with about 45 percent of the population in the U.S.,
14 percent in Canada, and 7 percent in Mexico. They rate a 6 out
of 20 on the Continental Concern Score and are not on the 2012 Watch
List. Great Horned Owls were heavily hunted until the practice was
abolished in the mid-twentieth century. Some illegal hunting continues.
Northern populations rise and fall in cycles along with prey populations.
The species adapts well to habitat change as long as nest sites
are available. In the Pacific Northwest they have expanded into
open land recently created by logging. Because of their prowess
as predators, Great Horned Owls can pose a threat to other species
of concern, such as Peregrine Falcons and Spotted Owls. Owls are
sometimes poisoned by pesticides and other toxic substances that
have accumulated in their prey.
|