Barred owl

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Barred owl
Strix-varia-005.jpg
Conservation status
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Aves
Order:Strigiformes
Family:Strigidae
Genus:Strix
Species:S. varia
Binomial name
Strix varia
Barton, 1799
Subspecies
  • S. v. georgica
  • S. v. helveola
  • S. v. sartorii
  • S. v. varia
Synonyms

Syrnium varium

 
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Barred owl
Strix-varia-005.jpg
Conservation status
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Aves
Order:Strigiformes
Family:Strigidae
Genus:Strix
Species:S. varia
Binomial name
Strix varia
Barton, 1799
Subspecies
  • S. v. georgica
  • S. v. helveola
  • S. v. sartorii
  • S. v. varia
Synonyms

Syrnium varium

The barred owl (Strix varia) is a large typical owl native to North America. Best known as the hoot owl for its distinctive call, it goes by many other names, including eight hooter, rain owl, wood owl, and striped owl.

Description[edit]

The adult is 40–63 cm (16–25 in) long with a 96–125 cm (38–49 in) wingspan. Weight in this species is 500 to 1,050 g (1.10 to 2.31 lb).[2] It has a pale face with dark rings around the eyes, a yellow beak and brown eyes. It is the only typical owl of the eastern United States which has brown eyes; all others have yellow eyes. The upper parts are mottled gray-brown. The underparts are light with markings; the chest is barred horizontally while the belly is streaked vertically. The legs and feet are covered in feathers up to the talons.[3] The head is round and lacks ear tufts, a distinction from the slightly smaller short-eared owl, which favors more open, marginal habitats.

Outside of the closely related spotted owl, this streaky, chunky-looking owl is unlikely to be confused over most of the range. The spotted owl is similar in appearance but has spots rather than streaks down the underside. Due to their fairly large size, the barred owl may be confused for the great horned owl by the inexperienced but are dramatically different in shape, eye color and markings.

Distribution and habitat[edit]

Breeding habitats are dense woods across Canada, the eastern United States, and south to Mexico;[1] in recent years it has spread to the northwestern United States, having gradually spread farther south in the west. The species is particularly numerous in a variety of wooded habitats in the southeastern United States. Recent studies show suburban neighborhoods can be ideal habitat for barred owls. Using transmitters, scientists found that populations increased faster in the suburban settings than in old growth forest. A factor of this suburban success may be easily accessible rodent prey in such settings. However, for breeding and roosting needs, this species needs at least some large trees and can be locally absent in some urban areas for this reason. The main danger to owls in suburban settings is from cars. The increased offspring offset the death rate due to impacts from cars and disease.[4]

Barred and the Northern Spotted Owl[edit]

Barred owls may be partly responsible for the recent decline of the northern spotted owl, native to British Columbia, Washington, Oregon, and California. Since the 1960s, barred owls have been expanding their range westward from the eastern US, perhaps because man-made changes have created new suitable habitat in the west.[5] When spotted owls and barred owls share the same environment, the latter are generally more aggressive and out-compete the former, leading to decreased populations of the native owls.[6] They have also been known to interbreed, with the hybrids named "sparred owl" or "botted owl", which are sterile, and further threaten the population stability of the Spotted Owl.[7]

On 5 April 2007, White House officials announced a U.S. Fish and Wildlife Service proposal to shoot barred owls to reduce the threat they pose to the spotted owl.[8] It called for constructing of eighteen sites in spotted owl territory where 12–32 barred owls would be taken per site.[8] Environmentalists fear increased blame on barred owls for declining spotted owl numbers will result in less attention being paid to territorial protection and resumption of logging in protected spotted owl habitat.[8]

Behavior[edit]

Barred owl near Blue Spring State Park, Florida

Reproduction[edit]

The barred owl's nest is often in a tree cavity, often ones created by pileated woodpeckers; it may also take over an old nesting site made previously by a red-shouldered hawk, Cooper's hawk, crow, or squirrel.[9] It is a permanent resident, but may wander after the nesting season. If a nest site has proved suitable in the past they will often reuse it as the birds are non-migratory. In the United States, eggs are laid from early-January in southern Florida to mid-April in northern Maine, and consist of 2 to 4 eggs per clutch. Eggs are brooded by the female with hatching taking place approximately 4 weeks later. Young owls fledge four to five weeks after hatching.[10] These owls have few predators, but young, unwary owls may be taken by cats. The most significant predator of barred owls is the great horned owl.[11] The barred owl has been known to live up to 10 years in the wild and 23 years in captivity.[2]

Food and feeding[edit]

The barred owl is a very opportunistic predator. The principal prey of this owl are meadow voles, followed by mice and shrews of various species. Other mammals preyed upon include rats, squirrels, rabbits, bats, moles, opossums, mink, and weasels. A barred owl was photographed in Minnesota in 2012 predaceously grabbing and flying with a full-grown domestic cat, a semi-regular prey item for the great horned owl but previously unknown to be taken by this species.[12] Birds are taken occasionally and commonly include woodpeckers, grouse, quails, jays, icterids, doves and pigeons, and even domestic ducks and chickens, where they will even swoop through small openings in enclosed and covered runs. Less commonly, other raptors are predated, including smaller owls.[11] Avian prey are typically taken as they settle into nocturnal roosts, because these owls are not generally nimble enough to catch birds on the wing. It occasionally wades into water to capture fish, turtles, frogs and crayfish.[3][13][14] Additional prey include snakes, lizards, salamanders, slugs, scorpions, beetles, crickets, and grasshoppers. Barred owls have been known to be attracted to campfires and lights where they forage for large insects. Prey is usually devoured on the spot. Larger prey is carried to a feeding perch and torn apart before eating.

The barred owl hunts by waiting on a high perch at night, or flying through the woods and swooping down on prey. A barred owl can sometimes be seen hunting before dark. This typically occurs during the nesting season or on dark and cloudy days. Of the North American owls, the pygmy, hawk, snowy and burrowing owls are more likely to be active during the day. Daytime activity is often most prevalent when barred owls are raising chicks.[3][14] However, this species still generally hunts near dawn or dusk.

Vocalization[edit]

The usual call is a series of eight accented hoots ending in oo-aw, with a downward pitch at the end. The most common mnemonic device for remembering the call is "Who cooks for you, who cooks for you all." It is noisy in most seasons. When agitated, this species will make a buzzy, rasping hiss and click its beak together forcefully. While calls are most common at night, the birds do call during the day as well.[15]

In art[edit]

John James Audubon illustrated the barred owl in Birds of America (published, London 1827-38) as Plate 46 where it is shown threatening a grey squirrel. The image was engraved and colored by Robert Havell's, London workshops. The original aquatint by Audubon is owned by the Brooklyn Museum.[16]

References[edit]

  1. ^ a b * BirdLife International (2012). "Strix varia". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 17 March 2014.  .
  2. ^ a b http://www.owlpages.com/owls.php?genus=Strix&species=varia
  3. ^ a b c Terres, J. K. (1980). The Audubon Society Encyclopedia of North American Birds. New York, NY: Knopf. p. 665. ISBN 0-394-46651-9. 
  4. ^ Owls Get Wise to Better Life in Cities, Jeanna Bryner, LiveScience Staff Writer, 2007
  5. ^ Barred Owl Displaces Northern Spotted Owl at Olympic, Scott Gremel, Natural Resources Year in Review, National Park System.
  6. ^ Using Ecological-Niche Modeling to Predict Barred Owl Invasions with Implications for Spotted Owl Conservation, A. Townsend Peterson and C. Richard Robins, Conservation Biology, pages 1161-1165, Volume 17, No. 4, August 2003
  7. ^ Interbreeding Threatens Rare Species, Experts Claim, Guynup, Sharon, National Geographic
  8. ^ a b c Durbin, Kathy. "White House Proposes Killing Spotted Owl Rival, Owls at Odds." The Columbian. 27 April 2007. NCCSP.org
  9. ^ Sattler, Helen Roney (1995). The Book of North American Owls. Clarion Books. p. 41. ISBN 0-395-60524-5. 
  10. ^ Barred Owl Factsheet, Lee and Rose Warner Nature Center, 2008
  11. ^ a b http://www.fcps.edu/islandcreekes/ecology/barred_owl.htm
  12. ^ "Pictured: The astonishing moment an owl snatched up a full-grown cat for a 'light' meal". London: Daily Mail. 28 October 2012. Retrieved 2013-01-08. 
  13. ^ Barred Owl, Owling
  14. ^ a b Habitat Suitability Index Models:Barred Owl, US Fish and Wildlife Service
  15. ^ Alderfer, Jonathan (2006). National Geographic: Complete Birds of North America. Washington D.C.: National Geographic Society. pp. 330–331. 
  16. ^ "Brooklyn Museum". Collections: American Art: Barred Owl. 

External links[edit]