Great Horned Owl

Great Horned Owl

Bubo virginianus Order: Strigiformes Family: Strigidae

Overview

Although often readily available through wildlife rehabilitation sources, previously wild, adult great horned owls can be challenging to manage while maintaining good welfare, even for the most experienced handlers.

To maximize lifelong welfare of an owl that is going to participate in ambassador animal programs, and as such be exposed to close contact with humans and a variety of stimuli that could otherwise be intimidating or inducive of unavoidable stress, it is recommended to hand-rear individuals slated to become ambassadors. Hand-rearing should occur during the formative stage of life, within the first few months of hatching. Hand-rearing owls allows the human caretaker to expose the owl from an early age to a variety of conditions it may encounter as an ambassador (crowds, vehicles, buildings, novel noises, etc.) while it is at the best stage to learn these stimuli are non-threatening, which generally helps them adapt to life under human care, in their roles as ambassadors, much more than parent-reared owls.

Natural History Information

Range and Habitat

Great horned owls are found throughout the United States and Canada, Central and South America. They live in forests, deserts, open country, swamps, and city park habitats.

Longevity

The average life expectancy of great horned owls is 13 years. The record for the longest life in the wild is 28 years old. In human care, the average lifespan is 20 years and the longest recorded lifespan is 35 years.

Ecosystem Role

Husbandry Information

Housing Requirements

Life Cycle Natural History Relevant Information

  • During the breeding season, both male and female individuals may demonstrate natural breeding behaviors that make them more challenging to work with and around. Consider time off from ambassador duties during this time.

Temperature, Humidity, Light Cycles

  • Great horned owls are found in both warm and cold climates. Typically, for healthy birds, no special temperature modification is necessary, although an overhead heat source during extreme cold is recommended. To note, in areas experiencing snow, it is most important to make sure perches are kept free of snow accumulation.

Substrate:

  • This species can be successfully managed on a variety of substrates, such as pea-gravel, sand, dirt, grass.

Social Housing/Colony Management

Other General Housing Requirements or Management information

  • Multiple perching options are necessary to maintain good foot health.
  • Having a perching area which is high and also in the corner gives the bird a sense of security and mimics natural behavior of perching on a branch near a tree trunk. It is also important to have both sun and shade areas in the exhibit, as well as an area which is covered so the bird can remove itself from the elements if need be.
  • Most owls do well with some kind of box or small shelter in their enclosure.
  • Space should meet minimum USFW standards.
  • Enclosure be constructed with materials that reduce the possibility of damage to the feathers or to the owl itself (for example, bare wire mesh is less desirable than vertical bars or coated mesh).
  • Flight-capable individuals need flight exercise to maintain muscle mass.
  • A double door mew entrance is ideal for any bird of prey. This allows handlers to enter the enclosure safely and without incident.

Diet Requirements

Diet in the Wild
  • Great horned owls eat an extremely wide range of prey species – at least 253 different species! Basically, great horned owls will eat anything that they can kill. That said, rabbits and hares are its preferred prey.

Diet under human care

  • Rats, mice, ducklings, chicks, quail, rabbit, and bird-of-prey diet.

Veterinary Concerns

  • Individuals with compromised ability, i.e. wild injured, should be constantly monitored for changes in quality of life due to injuries.
  • When working with birds with limited vision, complete blindness in one eye, or missing an eye, these birds seem to be more sensitive (displaying anxious behavior) to lighting changes. They also may be more sensitive to people approaching them from the “bad” side.

Enrichment & Training

Enrichment

Behavioral Relevant Information

  • Raptors seize and rip apart their prey. Offering whole prey items, shreddable enrichment items, items they can grab and manipulate with their talons or shred with their beaks are all good forms of enrichment.

Environmental Enrichment

  • Changing perches within their habitat.
  • Addition of browse.

Behavioral Enrichment

  • The most successful enrichment devices appear to be items that can be footed and shredded, such as paper products, cardboard boxes, lettuce, melons, squash or other produce. These items can be provided alone or stuffed with prey or diet, although raptors should be monitored for ingestion of foreign objects if food is delivered with a novel item. Other successful items include tennis balls, holl-ee rollers, and canvas dog toys, which present opportunities for seizing, grabbing, mock “killing,” and mantling.

Schedule

  • Daily enrichment is recommended.

Other Enrichment Resources

  • AZA’s Raptor TAG has a comprehensive list of raptor-appropriate enrichment as well as other suggestions on raptor enrichment programs on their website.

Training

Behaviors Trained

  • Voluntary step-up to glove
  • Voluntary loading into crate
  • Voluntary scale
  • Voluntary nail trim
  • A-B flights
  • Calm behavior on glove
  • Body palpation
  • Brandywine Zoo: trained a great horned owl for voluntary eye drops
  • Reinforcers used & schedule of reinforcement
    • Using food and/or weight management as part of a good behavioral management program facilitates training by creating a learning environment in which owls want to participate. Training strategies that involve reducing food offered to the point of compromising the health of the bird are considered unacceptable. Food management and weight management practices that are safe for the owl and trainers, provide for the health and welfare of the owl, and facilitate training are recommended.
    • Food and or weight management should be done with an understanding of the process and considerations. The decision to use weight management should not be taken lightly nor undertaken at all by staff who do not have a comprehensive understanding of managing weight and diet.

Other

Colony or Breeding Management

  • Notes species is housed or managed socially or for breeding purposes.

Individual Identification

  • Dimorphism or practiced ways to individually mark species (such as those in colonies, like giant millipedes).

Programmatic Information

Messaging Themes

Wild owl populations face a multitude of threats; fortunately, there are a number of individual and community-level actions that people can take to help to protect owls in the wild. Some examples are listed below.

Pesticide and Rodenticide use

As predators of rodents, all raptors, including owls, are incredibly vulnerable to rodenticide poisoning. Encourage responsibly use and properly manage rodenticides. Owls are also susceptible to pesticide biomagnification and mercury poisoning. Encourage people to avoid using pesticides on their lawns, and instead rely on native plantings or other environmentally responsible methods of pest management.

Human-Wildlife Interactions

Roadside litter is a threat to many owl species. Rodents are attracted to the litter, and a low-flying owl in pursuit of a rodent is vulnerable to a vehicular collision. Encourage visitors to dispose of their trash in an appropriate receptacle, not on the roadside, even if it is biodegradable. Owls are also susceptible to death through barbed wire or electrocution from power lines. We can help by supporting man-made barriers that keep birds away from high-electricity areas. Owls are highly sensitive nesters, and even slight disturbances can lead to abandonment. We can help by reducing activity in known nesting areas and avoiding owl nests when trimming trees or in forestry management.

Habitat Loss

Protecting habitat and supporting conservation organizations can help to protect populations of both predator and prey species.

Threats and Conservation Status

The only natural enemies of great horned owls are other great horned owls. Their range is wide and their numbers are abundant, so they have no special conservation status.

It is against the law to harass, harm, or kill any bird of prey. In addition, only licensed persons may rehabilitate an injured hawk or owl.

Prejudices against birds of prey still persist among many who wrongly believe that they harm wildlife or present major threats to domestic animals. Biological studies have documented their ecological importance as major controls on rodent populations. Some birds of prey feed on snakes, insects or other potential pests. No species of raptor poses a significant threat to domestic animals.

Interesting Natural History Information

Did you know…

  • Other common names are hoot owls, cat owls, or winged tigers.
  • Like other owl species, great horned owls can turn their heads almost 270 degrees. This movement is an adaptation because owls’ eyes cannot move in their sockets like other animals.
  • The first published description was made in 1788 by Johann Gmelin. It was first seen in the Virginia colonies, so the species name was created from the Latinised form of the name of that territory.

Handling & Presentation Tips

Use Guidelines

  • This species may be presented on glove, on perch, or in free-flight demonstrations. For tethered presentation, whether that is to the glove or to a perch, attention should be paid to avoid bating. Bating is not something that should be accepted from owls, if there are instances of such, it is an indication of discomfort, with the handler or the situation, and that discomfort should be addressed, not ignored.

Pubic Contact and Interaction Guidelines

  • Public contact with this species is not advisable.
  • Touching is not advisable.

Transportation Tips

  • Transport box suggestions Raptor Rig and Varikennel.
  • A couple things to keep in mind, crates should not be carried by the handle, but rather using two hands on either side of the crate and supporting it adequately. Swinging transport crates around and or moving them on a bumpy cart may create negative association for the bird, due to an uncomfortable ride and decrease the likelihood that the bird will go in the box on future occasions. If the perch is to low for the bird, their tail feathers may get painted with fecal matter which does not look good on presentation. Varikennel you are able to adjust the height of the perch.

Crating Techniques

  • This species can be trained to voluntarily enter a crate either from the glove or directly from their enclosure. Continuous reinforcement of voluntary crate behaviors as well as dedication to their comfort and safety while in the crate is important to maintaining solid and reliable crate behavior.

Temperature Guidelines

  • Being natural inhabitants of a variety of climates, great horned owls are typically able to be used in a wide variety of temperatures. When transporting and using on programs, attention should be paid to the comfort of the individual and any signs of heat distress responded to accordingly.

Acquisition Information

This species can be readily acquired from wildlife rehabilitators. See:

Resources

Contributors and Citations

  • The Philadelphia Zoo
  • Jacque Williamson, Brandywine Zoo
  • Helen Dishaw, Jackie Kozlowski, Tracy Aviary
  • Kit Lacy, Cascades Raptor Center
  • Amy Fennell, Natural Encounters, Inc.

Comments from the Rating System

  • Binhamton Zoo at Ross Park: Elderly owls in general have been an issue with traveling – they topple easily inside the owl box
  • Buffalo Zoo: Due to size and strength, handler should be experienced with birds of prey
  • Henry Vilas Zoo: Impressive for groups; hard to train; had several set-backs in handling/training
  • Maryland Zoo in Baltimore: Requires highly skilled handlers; males can become aggressive after maturity.
  • Philadelphia Zoo: Intimidating to novice handlers

Top Photo Credit: credit the “header” photo of the species