Great Horned Owl

Photo by: Marcia Nye

Good times to observe

Description

Average Length: 18-25 in., Wingspan: 36-60 in. Great Horned Owls are the largest year round resident owl in Illinois. They can vary in color from a reddish brown to a grey or black and white. Their underside is a light grey with dark bars and a white band of feathers on the upper breast giving them it a barred or mottled look that is excellent to camouflage themselves against tree trunks. They have large, yellow-orange eyes bordered in an orange/rusty facial disc. Their name is derived from tufts of feathers that appear to be “horns” which are sometimes referred to as the “ear tufts”, which have nothing to do with their ears or hearing at all. Their feet are feathered all the way down to their toes.

DuPage County Notes

Owls have spectacular binocular vision allowing them to pinpoint prey and see in low light. The eyes of Great Horned Owls are nearly as large as those of humans and are immobile within their circular bone sockets. Instead of turning their eyes, they turn their heads. Therefore, their neck must be able to turn a full 270 degrees in order to see in other directions without moving its entire body.

An owl's hearing is as good as – if not better than – its vision; they have better depth perception and better perception of sound elevation (up-down direction) than humans. This is due to owl ears not being placed in the same position on either side of their head: the right ear is typically set higher in the skull and at a slightly different angle. By tilting or turning its head until the sound is the same in each ear, an owl can pinpoint both the horizontal and vertical direction of a sound.

Great Horned Owls are some of the earliest-breeding birds in DuPage County. They breed in late January or early February and are often heard calling to each other in the fall, starting in October. They choose a mate by December and are often heard duetting before this time. Both sexes may be very aggressive towards intruders when nesting.

They often take over a nest used by some other large bird, sometimes adding feathers to line the nest but usually not much more. Old crow, Red-tailed Hawk or large squirrel nests are often favored in North America. However, they are far from dependent on the old nests of others and may use cavities in trees and snags, cliffs, deserted buildings, and artificial platforms.

Even though the female Great Horned Owl is larger than her mate, the male has a deeper voice. Pairs often call together, with audible differences in pitch.

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.

An extremely wide range of prey species (over 250 identified) are captured, but rabbits and hares are its preferred prey. Mammalian prey includes all coexisting rodents, squirrels, mink, skunks, raccoons, armadillos, porcupines, shrews, moles, muskrats, and bats. The Great Horned Owl is the only animal that regularly eats skunks.

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 red-tailed hawk.

Great Horned Owls are found throughout North America from the northern treeline and then in Central and South America. They are resident year-round in Illinois, however, birds living in the northern part of the species' range may migrate south.

Activity generally begins at dusk

Most recent observations

User contributed image from Mike Shimer containing Great Horned Owl on Willowbrook Preserve 2 weeks 2 days ago at Willowbrook, Mike Shimer observed...
Last Sunday afternoon at Willowbrook Wildlife Center. Anne Marie Smith "RVI" was conducting encounters with Andrea one of two Great Horned Owls that are utilized in educational programs....
User contributed image from Carl Strang containing Great Horned Owl on Warrenville Grove Preserve 5 months 1 week ago at Warrenville Grove, Carl Strang observed...
A pair of great horned owls were duetting in Warrenville Grove Forest Preserve at dusk yesterday (note: photo from another occasion, at Winfield Mounds).

Nature Notes

DuPage River West Branch Observe Your Preserve Fall Color Canoe Trip

David Guritz, 5 months 1 week ago - Saturday, October 12, 2013 It's hard to imagine a better opportunity to...
brown moth perched on a twig

Endings and Beginnings

Carl Strang, 5 months 3 weeks ago - We like to think of the seasons as blocks, and to relate them to our own lives. As the season we call winter approaches, we think in terms of furnace tune-ups, digging...
An expanse of mud with some plants growing in it, but no water.

Mayslake July Natural History Summary

Carl Strang, 1 year 8 months ago - July’s weather was very hot and dry, with many days reaching the 90’s and 100’s F (this was the hottest July on record for the 48 contiguous...
Young great horned owl perched on a branch.

Mayslake in May

Carl Strang, 1 year 10 months ago - May’s weather was essentially seasonal, but the warm early part of the year continued to have its influence. Plants continued to bloom earlier than in recent years, a median of 16 days...
A great horned owl peers out from above a squirrel nest in a pine tree.

It Takes a Village...

Carl Strang, 2 years 1 day ago - This year, Mayslake Forest Preserve’s pair of great horned owls decided to use a squirrel nest for their own breeding attempt. In my first sweep of the preserve I did not find the...

Typical and characteristic habitat

Preserves where you might see this species

 

Habitats in DuPage County where this species has been recorded