Great Horned Owl

STATUSLeast Concern

COMMON NAME (SCIENTIFIC NAME)Bubo virginianus

DIETSkunks, rabbits, squirrels, rats and mice, small birds, fish, reptiles, amphibians, and even insects

RANGENorth America with a range extending into Central and South America

HABITATWooded regions, swamps, deserts, farmlands and suburban/urban areas

Great Horned Owl

 The Great Horned Owl (GOH) has a body length of 46-63 cm, a wingspan up to 145cm, and can weigh up to 2500g.

The scientific name comes from the Latin word bubo, which refers to an owl, and the Latinized name for the state of Virginia, where the first specimen was taken for scientific collection. The common name refers to the large size of the bird and the feather tufts on its head. This owl has also been called Big Hoot Owl, Cat Owl, Chicken Owl, Eagle Owl, Horned Owl, and King Owl. ( http://www.peregrinefund.org/subsites/explore-raptors-2001/owls/grethorn.html)

Great horned owls are mottled browns and black with a darker back and lighter, barred belly although colorations vary with each individual. They have a white area on their throat. These birds also have feathered tufts on their head that are usually darker in color than much of the body and are used to help them camouflage in their environment. With beautiful yellow eyes and a black beak, the face of a great horned owl is made even more distinct by its white eyebrows. An immature GOH has the same coloring as an adult. Males and females of the species cannot be determined by coloration, but females are often slightly larger than males (weighing more).

 Great horned owls are nocturnal and their “hoo hoo” call can be heard throughout the night.

Related To:
Screech owls, Eurasian eagle owls.

Habitat/Range:  Geographically, GHOs are found through most of North American with a range extending into Central and even parts of South America. The species uses habitats ranging from wooded regions, swamps, and deserts to farmlands and suburban/urban areas.

Diet in Wild:  Great horned owls have a large variety of food items they will hunt and eat. Medium to small mammals such as rabbits, squirrels, rats and mice are preferred species on the menu but a GHO will also readily capture and eat other birds (including smaller owls such as the screech-owl), fish, reptiles, amphibians, and even insects. The geographic region in which the owl lives is the greatest determining factor in what their diet consists of. These birds hunt starting at dusk and through the night. Some have even been known to hope on the ground or wade into water to capture prey. In cases where food is scarce, a great horned owl may also eat carrion.

Diet in Zoo:  Bird of Prey diet (commercially prepared and humanely killed), mice and chicks.  Frozen packaging not only ensures freshness but also cleanliness.  Also keep in mind that all of the Education Birds of Prey are not able to hunt on their own in the wild so live prey would be difficult for many of them anyway. Diet enrichments ensure stimulation for the birds.

Predators:  Being an apex predator, there is no other species that regularly preys on the great horned owl. In some cases, a raccoon or another nest robbing animal may steal an egg or prey upon a hatchling. For the most part, however, humans are the species that pose the biggest threat to great horned owls. Hunting along the road side increases the risk of bird-car collisions.

Life Cycle and Social Structure:  Great horned owls reach sexual maturity between 1 and 3 years of age. They are monogamous and protect their territories from other breeding pairs. Courtship between male and female includes a hooting to each other.  For this reason, males may call all year long to protect and define territories, but females generally only hoot during the breeding season when courting with a mate.

Once a pair has bonded to each other, they will select a suitable nest site. Great horned owls do not build a nest and thus claim vacant stick nests of squirrels or other bird species as well as tree cavities and some buildings. They may also nest on cliff ledges. While the amount of eggs laid in a brood tends to vary per region and based on food availability, in general great horned owls lay somewhere between 1 and 3 white, spherical eggs in a season.

Males and females share the responsibility of taking care of their young. Both will protect the nest and incubate the eggs and both will hunt although once the chicks are hatched, males spend more time hunting leaving the females behind to guard the nest. It has been noted, however, that during seasons when food is scarce both parents will go hunting at the same time and leave the nest unattended. Young may be cared for by their parents for up to 5 months of their lives.

During most of the year great horned owls are solitary (the exception being breeding season). They establish territories which they defend by hooting to announce their presence and ownership of the area to other owls. Those owls who are too young to have developed their own home ranges float on the boarders of other birds territories and remain mostly silent as to not draw unwanted attention to themselves. These owls are not migratory and stay in their home range year round.

Life Span: On average, great horned owls in the wild live between 13 to 15 years of age but on occasion can live into their late twenties (the oldest wild GHO on record having lived 28 years). Like most animals, these birds live longer in captivity with an average life expectancy of 20-25 years old but sometimes reaching as old as 35 years of age.

 Interesting Facts: 

  • The great horned owl is referred to as “the tiger of the sky” because of its fierce nature and ability to capture a wide variety of prey that may be larger or heavier than the owl.
  • The great horned owl is the only animal regularly known to prey on skunks.
  • Great horned owls often get mobbed by other birds such as song birds and crows who call at them for extended periods of time to drive them away from an area
  • Female GHOs have a higher pitched call than male GHOs even though they are larger in size

Conservation Message:  Important Predators:  Owls like other birds of prey are very important predators.  Owls usually consume insects and small rodents which keeps the pest population low.  They are very beneficial to farmers and our ecosystems. Being that they easily adapt to living in urban areas, they also help control pest species in towns and cities.

What You Can Do:
Do not litter: Birds of prey can be seen hunting along highways all over the country which is very dangerous for them, many of them are hit by cars or somehow injured along the roadways.  They are attracted the roadways because their prey is attracted to the roadways and their prey (mice, rats, rabbits, opossums, raccoons, smaller birds, etc.) are attracted to the trash along the side of the road.  Everyone can make a positive impact by not littering or even volunteering to remove garbage from the roads.  Although many people may not consider apple cores or banana peels to be “litter”, it can still attract animals the roadside. Taking it home and disposing of it properly can help a bird of prey near you.

Imprinting:
If you find an injured or orphaned animal call a licensed wildlife rehabilitation center in your area.  They have proper permits and training to hopefully get the animal out on its own in the wild.

If you find a baby bird and it doesn’t appear to be injured and it’s not in immediate danger (like a predator near by; ie: house cat), it is best to leave the bird there.  Its parents are probably looking on from afar and will return to it and care and feed it.  If you are sure which nest it fell from it is safe to pick it up and return it safely to its nest.  It’s not true that the parents will smell your scent and not care for the bird anymore, remember most bird have a very weak sense of smell.

If an untrained person tries to care for the bird then the bird will be acclimated to people and never learn to survive on its own in the wild.  (How can a person teach a bird to hunt, migrate, and fend for itself)?  Most birds and some other animals bond with their caregivers and the larger animals first visible to them when their young, whether or not its their actual parents…we call this imprinting which is what happened with one of the Lehigh Valley Zoo’s great horned owls.

Bibliography
http://animaldiversity.ummz.umich.edu/
http://www.allaboutbirds.org/
http://www.peregrinefund.org/