Spotted Owl

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(Mexican) Spotted Owl
northern race plumage
northern race plumage
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Strix
Species: S. occidentalis
Binomial name
Strix occidentalis
Xantus de Vesey, 1860

The Spotted Owl, Strix occidentalis, is a species of owl. It is a resident species of forests in western North America, where it nests in tree holes, old bird of prey nests, or rock crevices. Nests can be between 13 and 66 yards (12 to 60 meters) high and usually contain two eggs (though some will contain as many as four). It is a strictly nocturnal owl, which feeds on small mammals and birds.

This owl has a length of 43 cm (17 inches), a wingspan of 114 cm (45 inches, and a weight of around 600 g (21 ounces). Its eggs are a little over 2 inches (50 millimeters) long, and are white and smooth with a slightly grainy texture. The female sits on the eggs and cares for the young, while the male provides food for them.

The three sub-species of Strix occidentalis are Strix occidentalis caurina (Northern Spotted Owl), Strix occidentalis occidentalis (California Spotted Owl), and Strix occidentalis lucida (often referred to as the Mexican Spotted Owl).[1] The Gila Wilderness is home to the largest population of the Mexican sub-species.[2]

The Spotted Owl is similar in appearance to the Barred Owl but has cross-shaped markings on the underparts whereas the Barred Owl is alternately barred on the breast and streaked on the belly. Barred Owls are larger and grayer than Spotted Owls. In recent years the California and Northern subspecies of Spotted Owl have been displaced by Barred Owls, which are more aggressive, have a broader diet and occur in more varied habitats. Though the two species may hybridize in areas where displacement is occurring, they are quite genetically distinct, for example, differing 13.9% in certain gene sequences. [3]

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[edit] Conservation

The Northern and Mexican spotted owl populations currently have endangered status in the United States, according to the United States Fish and Wildlife Service (USFWS). The California spotted owl is is not considered to be threatened nor endangered by the USFWS, however, it it considered to be a species of special concern by the state of California and the United States Forest Service (USFS). All subspecies of the spotted owl are often the subject of disagreement between conservationists and loggers, cattle grazers, developers, and other organizations whose activities can affect forest cover. In February 2008, a federal judge reinforced a U.S. Fish and Wildlife Service decision to designate 8,600,000 acres (34,800 km²) in Arizona, Utah, Colorado and New Mexico as critical habitat for the owl. The decision had been challenged by the Arizona Cattle Growers' Association, but Judge Susan Bolton upheld the designation. According to the Center for Biological diversity, "Having critical habitat will ensure that U.S. Forest Service logging does not limit the bird's recovery or drive it into extinction."[4]

[edit] Gallery

[edit] References

  1. ^ Condor107:182
  2. ^ Mexican Spotted Owl Recovery Program at U.S. Fish and Wildlife Service.
  3. ^ Haig SM, Mullins TD, Forsman ED, Trail PW, & Wennerberg L. 2004. Genetic identification of spotted owls, barred owls, and their hybrids: legal implications of hybrid identity. Conservation Biology 18(5):1347-1357
  4. ^ Habitat for Mexican spotted owl to stand

Anthony, R. G. et al. 2006. Status and trends in demography of northern spotted owls, 1985–2003. Wildl. Monogr. 163, 1–47

Courtney SP, Franklin A (2004) Information Needs. In: et al., editor. Scientific evaluation of the status of the Northern Spotted Owl. Portland, OR: Sustainable Ecosystems Institute. pp. 1-18.

Dark SJ, Gutierrez RJ, Gould GI (1998) The invasion of Barred Owls (Strix varia) in California: Potential impacts on the Spotted Owl (Strix occidentalis). The Auk 115: 50-56.

Funk, W.C., E.D. Forsman, T.D. Mullins, and S.M. Haig. 2008 Mountains and valleys shape genetic structure of northern spotted owls (Strix occidentalis caurina). Evolutionary Applications.

Funk, W.C., T.D. Mullins, E.D. Forsman, and S.M. Haig. 2007. Microsatellite markers for distinguishing Spotted Owls (Strix occidentalis), Barred Owls (S. varia), and their hybrids. Molecular Ecology Notes 7: 285-286.

Gutiérrez RJ, Franklin AB, Lahaye WS (1995) Spotted Owl (Strix occidentalis). In: Gill F, editor. The American Ornithologists' Union. Philadelphia, PA: The Academy of Natural Sciences and Washington DC.

Gutiérrez RJ (1989) Hematozoa from the Spotted Owl. Journal of Wildlife Diseases 25: 614-618.

Haig, S.M., E.D. Forsman, and T.D. Mullins. 2004. Subspecific relationships and genetic structure in the Spotted Owl. Conservation Genetics 5: 683-705.

Haig, S.M., T.D. Mullins, E.D. Forsman, P. Trail and L. Wennerberg. 2004. Genetic identification of Spotted Owls, Barred Owls, and their hybrids: evolutionary and legal implications. Conservation Biology 18: 1347-1357.

Haig, S.M., R.S. Wagner, E.D. Forsman, and T.D. Mullins. 2001. Geographic variation and genetic structure in Spotted Owls. Conservation Genetics 2: 25-40.

La Haye W (2004) Northern Spotted Owl Biology. In: et al., editor. Scientific evaluation of the status of the Northern Spotted Owl. Portland, OR: Sustainable Ecosystems Institute. pp. 2, 9.

Monahan WB, Hijmans RJ (2007) Distributional dynamics of invasion and hybridization by Strix spp. in Western North America. Ornithological Monographs 63: 55-66.

Noon BR, Franklin AB (2002) Scientific research and the Spotted Owl (Strix occidentalis): opportunities for major contributions to avian population ecology. The Auk 119: 1291-1298.

Noon, B. R. & Blakesley, J. A. 2006. Conservation of the northern spotted owl under the Northwest Forest Plan. Conserv. Biol. 20, 288–296.

Taylor AL, Forsman ED (1976) Recent range extensions of the Barred Owl in Western North American including the first records for Oregon. Condor 78: 560-561.

U.S. Fish and Wildlife Service. 1990. Endangered and threatened wildlife and plants: determination of threatened status of the northern spotted owl. Federal Register 55, 26114–26194.

U.S. Department of the Interior (2006) U.S. Fish and Wildlife Service. Endangered and Threatened Wildlife and Plants: 12 month finding a petition to list the California Spotted Owl (Strix occidentalis occidentalis) as Threatened or Endangered. Federal Register, Part XVII 71: 100.

U.S. Fish and Wildlife Service (2007) Background and Q&A's about the 12-month finding on the petition to list the California spotted owl. Sacramento Fish and Wildlife Office.

[edit] External links

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