Barred owl (Strix varia)

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Barred owl fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Barred owl description

The barred owl (Strix varia) is a rather large, round, chunky owl with a large, grey-brown head and a pale, well-developed facial disc. Dark, concentric lines circle the face, which also features a pale yellow bill and big brown eyes ^{(2) (3) (5) (6)}. The upperparts of the barred owl are grey-brown or brown and are scalloped white-buff. The darkest barring within the plumage occurs on the upper breast, head and throat ^{(3) (5) (7)}.

The underparts of the barred owl are pale grey-brown to off-white, with dark, bold streaking running vertically up the belly and onto the breast, which is streaked horizontally ^{(2) (3) (5)}. The talons are horn-like in colouration, gradually becoming darker towards the tips ^{(2) (3)}. The barred owl’s legs and feet are feathered, except in southern populations, where the dull yellow toes can be seen ^{(2) (3) (5)}. The tail is dark brown or grey-brown with four or five whitish bars ^{(2) (3)}, and this barring is also seen on the flight feathers on the wing ⁽³⁾.

The female barred owl is slightly larger and heavier than the male ⁽²⁾. Barred owl hatchlings have soft, pure white down feathers, which are partially present until the full adult plumage is attained ^{(2) (3)}. The markings of the juvenile are less distinct than in the adult, especially around the head ⁽²⁾.

The characteristic hooting of the barred owl is a rhythmic ‘hoo-hoo-to-hoo-ooo, hoo-hoo-hoo-to-whooo-ooo’ ⁽²⁾, which is often transcribed as ‘I cook for you’ ^{(2) (3)}. As well as this highly distinctive call, during courtship the male and female barred owl perform impressive vocal duets ⁽²⁾.

There are four recognised subspecies of barred owl: Strix varia varia, Strix varia georgica, Strix varia helveola, and Strix varia sartorii. These subspecies are known to differ in colour and in the extent of feathering on the legs, as well as in range and size, with southern individuals usually being smaller and darker with relatively featherless legs ⁽²⁾.

Also known as

eight hooter, hoot owl, rain owl, striped owl, wood owl.

Size

Length: 43 - 50 cm ⁽²⁾

Wingspan: c. 111 cm ⁽⁴⁾

Male weight: c. 630 g ⁽³⁾

Female weight: c. 800 g ⁽³⁾

Barred owl biology

A highly territorial species, the barred owl defends its territory by singing from various perches surrounding the area and is aggressive towards intruders ^{(2) (3)}. The barred owl is nocturnal and roosts within the dense foliage of trees during the day, usually positioning itself high above the ground, close to the trunk or in a cavity in the tree ⁽³⁾.

Although the barred owl is usually solitary outside of the breeding season, males and females form monogamous pairs during the breeding season to raise a single brood each year ⁽²⁾. Nest sites are usually located in tree cavities, or existing nests built by other species may be used, with other material very rarely being added to the nest ^{(3) (4) (5)}. Eggs are typically laid between March and April, but may be laid later in the northern parts of the barred owl’s range ⁽²⁾. The average clutch of the female barred owl contains 2 or 3 slightly rough white eggs, which are incubated solely by the female for between 28 and 33 days ^{(2) (3)}. During the incubation period the male will infrequently return to the nest with food for the female ⁽²⁾. When the eggs have hatched, the hatchlings are brooded by the female. After around four or five weeks they leave the nest and are cared for by both the male and female for several more weeks ^{(2) (3)}. The young barred owls begin to lose their down feathers and moult into their adult plumage after around six weeks, gaining the full adult plumage after five or six months ⁽²⁾.

The diet of the barred owl is mainly composed of small mammals such as voles, mice, rats, shrews, moles and chipmunks ^{(2) (3) (5)}. An opportunistic predator, the barred owl also takes amphibians, reptiles and invertebrates ⁽²⁾. S. v. georgica has been known to eat armadillos and young alligators ^{(2) (3)}. Hunting generally occurs at dawn or dusk ⁽⁵⁾, with the barred owl waiting atop/on an elevated perch until it detects potential prey ^{(2) (3) (5)}. Night-roosting birds are also caught by chasing them from their roosts ⁽³⁾.

The barred owl is mostly non-migratory, and will generally move only during times of poor food availability ^{(2) (3)}. However, northern populations may occasionally migrate south in winter ⁽²⁾.

Barred owl range

The barred owl is widely distributed throughout Canada, the United States and Mexico ^{(3) (5) (8)}. The range of this widespread species is currently extending into the western United States ⁽³⁾, and it is also sometimes found as a vagrant in Bermuda ⁽⁸⁾. 

Barred owl habitat

The barred owl generally inhabits mature, dense coniferous, deciduous, mixed or boreal woodland, where there are many available nesting and roosting sites ^{(2) (3) (5) (6)}. It is also found in the mature wooded areas surrounding swamps and rivers ^{(2) (3) (7)}.

Semi-forested areas are also inhabited by the barred owl, although continuous woodland is usually preferred ⁽³⁾. Recently, this widespread bird has also begun to inhabit the temperate rainforests in the northwest of its range ⁽⁶⁾.

Barred owl status

The barred owl is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Barred owl threats

The barred owl, like other owls, is threatened by collisions with road traffic and being caught in traps for other species, although these are not thought to be responsible for high levels of mortality. Hybridisation with the threatened spotted owl (Strix occidentalis) is also a threat to this species ⁽²⁾.

The most significant threat to the barred owl is the modification of its habitat through deforestation ⁽²⁾. Planting young trees to replace older trees is not necessarily beneficial for this species, as it relies on the cavities in older trees to nest, as well as on nests made in previous years by other species ⁽³⁾. In the eastern United States and Canada, available habitat for the barred owl has been reduced by agriculture and urbanisation ⁽²⁾.

Barred owl conservation

There are not known to be any specific conservation measures currently in place for the barred owl, although it would benefit from research into its biology, nutrition, disease, and the impacts of industrial logging on the overall population. Hybridisation with the spotted owl must also be closely monitored to ensure the survival of both owl species ⁽²⁾.

Find out more

Find out more about the barred owl and its conservation:

• The Cornell Laboratory of Ornithology: All About Birds - Barred owl:
  http://www.allaboutbirds.org/guide/Barred_owl/id/ac
• BirdLife International - Barred owl:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=2243

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Glossary

Boreal forest

The sub-Arctic forest of the high northern latitudes that surrounds the North Pole and is mainly composed of coniferous trees.

Deciduous forest

Forest consisting mainly of deciduous trees, which shed their leaves at the end of the growing season.

Flight feathers

The feathers at the end of the wing, involved in flight.

Hybridisation

Cross-breeding between two different species or subspecies.

Incubate

To keep eggs warm so that development is possible.

Invertebrates

Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.

Monogamous

Having only one mate during a breeding season, or throughout the breeding life of a pair.

Moult

Periodic shedding of (usually) the outermost body covering (such as feathers, fur or skin) during growth and development, or at specific times of the year.

Nocturnal

Active at night.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

Territorial

Describes an animal, a pair of animals or a group that occupies and defends an area.

Territory

An area occupied and defended by an animal, a pair of animals or a group.

Vagrant

An individual found outside the normal range of the species.

References

1. IUCN Red List (March, 2012)
   http://www.iucnredlist.org/
2. Mazur, K.M. and James, P.C. (2000) Barred owl (Strix varia) In: Poole, A. (Ed.) The Birds of North America Online. Cornell Lab of Ornithology, Ithaca. Available at:
   http://bna.birds.cornell.edu/bna/species/508
3. König, C. and Weick, F. (2008) Owls of the World. Christopher Helm, London.
4. Deal, K.H. (2010) Wildlife and Natural Resource Management. Delmar Cengage Learning, New York.
5. MobileReference (2008) The Illustrated Encyclopedia Of North American Birds: An Essential Guide To Birds Of North America. MobileReference, Boston.
6. Lynch, W. (2007) Owls of the United States and Canada:A Complete Guide to Their Biology and Behaviour. Johns Hopkins University Press, Maryland.
7. Dunn, J. and Alderfer, J.K. (2006) National Geographic Field Guide to the Birds of North America. National Geographic Books, Washington.
8. BirdLife International (March, 2012)
   http://www.birdlife.org/datazone/speciesfactsheet.php?id=2243