Home | Bird Species Profiles | The Great Horned Owl, Bubo virginianus – Encounters in Nature and Captivity, Part I – Natural History

The Great Horned Owl, Bubo virginianus – Encounters in Nature and Captivity, Part I – Natural History

Great Horned OwlToday I’d like to cover a bird that, while generally illegal to keep in the USA, is one of the largest and most impressive species that might reasonably be encountered anywhere within the USA, and beyond – the Great Horned Owl.

Their occasional propensity for living near people (until recently, a pair nested in Battery Park, Manhattan) results in a number being injured each year.  I have cared for several such birds, and suggest that anyone interested in doing likewise apply for the necessary state permits and seek training as a Wildlife Rehabilitator.  Hand-raised Great Horned Owls are gaining popularity with European aviculturists, and a few are even used, falconry style, to hunt game.

Physical Description
One of the largest of the world’s 135 owl species, in the Western Hemisphere the Great Horned is exceeded in size only by the Great Gray Owl (which it outweighs) and the Snowy Owl.  It reaches 25 inches in length, and the wings may span 5 feet (sizes vary greatly among various populations).

The eyes are bright yellow, the throat white and the head is topped with prominent ear tufts.  The color ranges from white in the Arctic to near black along the Pacific coast, but most individuals are varying shades of mottled tan, brown or dark gray.  Females may be up to 20% larger than males.
The vast range encompasses nearly all of North and South America.  At least 13 subspecies are found from northern Alaska and Labrador through the southern 2/3 of Canada, in all 48 lower states and Mexico and south to the extreme southern tip of South America.  Only the Barn Owl, which lives on all continents except Antarctica, is more widespread.

Extremely varied, including tundra, deserts, swamps, grasslands, agricultural areas, city parks, mixed and coniferous forest, salt marsh, rainforest edges and mountain slopes.

Densities can be quite high in prime habitat.  Suburban areas, with their mix of towns, fields, forests and parks, prove quite inviting to Great Horned Owls.  Wildlife rehabilitators on Long Island, NY rarely release birds there as nearly every suitable area has been claimed by a nesting pair.

I have found Great Horned Owls nesting in California desert caves and abandoned buildings in NYC, along a salt water bay in a NYC suburb, at a rainforest edge in Costa Rica and on farms in the Venezuelan llanos.

This is our most powerful owl, and one of the world’s most formidable avian predators.  Over 260 prey species have been recorded, including raccoons, opossums, muskrats, flying squirrels and other rodents, smaller owls and birds to the size of red-tailed hawks and great blue herons,  small alligators, snakes, turtles and frogs, large insects, fish (will wade in shallow water) and road-killed animals.

It is one of the few predators that regularly takes striped skunks and porcupines.  It will, in most “un owl-like” fashion, do battle on the ground – I still recall a striking series of photos from the 1960’s Time-Life Nature Library Series depicting a Great Horned Owl “wrestling” with (and nearly losing its life to) a large bullsnake.

Owls living near farms take ducks, turkeys, geese and other fowl, and have been observed walking into coops to snatch chickens.  In NYC and other urban areas, Great Horned Owls feed largely upon rats and roosting pigeons, but have been known to take domestic cats.

In the northeastern USA, mating occurs in January, and females are incubating eggs by February, when snows are still likely.  The owls often appropriate the nests of red-tailed hawks and other large birds – sometimes driving off or even killing the owners.  Depending upon the habitat, rock ledges, tree cavities, abandoned buildings, barns, large cactus plants or even the ground may serve as a nest site.

The female lays 1-5 eggs and incubates the clutch for 35-40 days (males in some populations may incubate as well).  The young are fed by both parents and fledge in 8-10 weeks.

Both parents are extremely aggressive in defending the nest, and quite literally will not cease their attacks until the intruder, human or otherwise, has been driven off.  A coworker of mine at the Bronx Zoo once entered a pair’s exhibit without a hard hat and landed in the hospital with severe scalp lacerations as a result.

Great Horned Owl pairs defend specific home territories for many years, but forage singly outside of the breeding season.

Owls are often referred to as “Birds of Prey”, along with hawks, falcons, eagles and vultures.  They are not, however, related to any of these birds.

Great Horned Owls are classified within the owl family Bubonidae (the Eagle Owls) and are the only representative of the group to dwell in the Americas.  Eleven other eagle owl species, all large, formidable predators (the massive European eagle owl occasionally takes deer fawns), are found in Europe, Africa and Asia.  In terms of their role in the environment, eagle owls are considered to be the nocturnal equivalent of the diurnal eagles and larger hawks.

Next time I’ll discuss Great Horned Owls in captivity, and relay a few personal experiences.

Further information on the Great Horned Owl, including photos and voice recordings, is posted at:

Image originally posted by Billy Hunt and referenced from Wikipedia Commons.


  1. avatar

    I found your blog and read a few of the posts. Keep up the good work. I am looking forward to checking out more from you in the future.

  2. avatar

    Hello Dan, Frank Indiviglio here.

    Thanks for your interest in our blog and the kind comment. I’m glad you are enjoying my articles…I look forward to your comments.

    Best regards, Frank Indiviglio.

  3. avatar

    I am pretty sure that we have a great horned owl living on our property. I would like to take pictures of it if I could find it. When is a good time to take pictures of it when we only here it at night?

  4. avatar

    Hello Kari, Frank Indiviglio here.

    Thanks for your interest in our blog. I hope you get to see the owl, they are very impressive. They hunt at night, and so might be hard to locate. In cold climates with short days (not sure where you are) owls may move about on overcast days, especially if food is in short supply. If you have a chance to look around by day, check below trees for pellets – regurgitate remains of prey (hair, fur, feathers) – this will guide you to it’s favorite perch. In cold weather they favor pines if available. Listen for calls also, they usually court in Feb. and often nest during that month as well.

    Good luck and please let me know how it turns out,

    Best regards, Frank Indiviglio.

  5. avatar

    Hello Frank

    I have always been fascinated with the GHO because of its hunting prowess. I have read from different sources of its ability to capture domestic cats, which is quite impressive because its usually the other way around. Have you ever witnessed a GHO capturing a cat or seen the remains near a nest or perch.

  6. avatar

    Hello Jason, Frank Indiviglio here.

    Thanks for your interest in our blog.

    Same here, they have always been a favorite of mine. Skunks and even porcupines are said to be on their menu as well. I’ve not found cat remains in pellets, but a park ranger at Van Courtland Park (Bronx, NY) informed me that he had, as has a former student of mine. I believe I read a good account of same in the book The World of the Great Horned Owl. The book The Birds, in the 1960’s Time Life Series, has an amazing photo sequence of a GHO battling a large snake (Coachwhip, perhaps?) on the ground, in a desert habitat.

    Check out Understanding Owls, as well, for insights on captive rearing/ training of these and others.

    Good luck and please keep me posted. Hope to hear from you again in the future,

    Best regards, Frank Indiviglio.

  7. avatar

    Just a quick note on this as well:

    When using notation for aves, there is a standardized AOU format that assigns a unique 4 letter code for every bird in the US. Great Horned Owl, has the coding GHOW. I realize you both were merely abbreviating, but there is a standardized way, and for the sake of staying professional it’s always helpful to be used.


  8. avatar

    Hello Cody, Frank Indiviglio here.

    Thanks for the info. I tend to rely on Latin names to cover ID; most folks are unaware of the American Ornithologist’s Union guidelines. I do, however, sometimes post research updates drawn for The Auk and other professional journals, and can mention standardized common names at that time.

    Best regards, Frank Indiviglio.

About Frank Indiviglio

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I believe that I was born with an intense interest in animals, as neither I nor any of my family can recall a time when I was not fascinated by creatures large and small. One might imagine this to be an unfortunate set of circumstances for a person born and raised in the Bronx, but, in actuality, quite the opposite was true. Most importantly, my family encouraged both my interest and the extensive menagerie that sprung from it. My mother and grandmother somehow found ways to cope with the skunks, flying squirrels, octopus, caimans and countless other odd creatures that routinely arrived un-announced at our front door. Assisting in hand-feeding hatchling praying mantises and in eradicating hoards of mosquitoes (I once thought I had discovered “fresh-water brine shrimp” and stocked my tanks with thousands of mosquito larvae!) became second nature to them. My mother went on to become a serious naturalist, and has helped thousands learn about wildlife in her 16 years as a volunteer at the Bronx Zoo. My grandfather actively conspired in my zoo-buildings efforts, regularly appearing with chipmunks, boa constrictors, turtles rescued from the Fulton Fish Market and, especially, unusual marine creatures. It was his passion for seahorses that led me to write a book about them years later. Thank you very much, for a complete biography of my experience click here.
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