Species: Strix nebulosa

Great Gray Owl

Species

Birds

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Terrestrial vertebrates: birds

Encyclopedia of Puget Sound

Classification

Kingdom

Animalia

Phylum

Craniata

Class

Aves

Order

Strigiformes

Family

Strigidae

Genus

Strix

NatureServe

Source:
ELEMENT_GLOBAL.2.100756

Classification

Other Global Common Names

Great Grey Owl - chouette lapone

Informal Taxonomy

Animals, Vertebrates - Birds - Other Birds

Formal Taxonomy

Animalia - Craniata - Aves - Strigiformes - Strigidae - Strix

Ecology and Life History

Short General Description

A very large owl.

Migration

true - false - false - Greater mobility exhibited in years when food scarce (Duncan 1987). Food scarcity or unavailability may cause post-breeding movement upslope and downslope movement in winter (California Department of Fish and Game 1990). May move several hundred km southward for winter; in some areas, longest movements made by immatures (but see ECOLCOM).

Non-migrant

true

Locally Migrant

false

Food Comments

Diet in North America dominated by pocket gophers and voles. Forages usually in open area where scattered trees or forest margin provides suitable sites for visual searching; also uses sound to locate prey under snow cover.

Reproduction Comments

Egg dates: late March-May in Alberta, late April-early June in Ontario, peak mid-April to late May in California, mean date of first egg 5 May in southern Idaho and northwestern Wyoming; eggs laying may be delayed in years with deep snow (Franklin 1988). Clutch size is 2-5 (usually 2-3 or 3-4). Incubation lasts 28-29 days, by female (male brings food). Young begin to leave nest at 3-4 weeks (4 weeks in Idaho/Wyoming), fly well at 5-6 weeks (6 weeks in Idaho/Wyoming), independent at about 4-5 months (Idaho/Wyoming: Franklin 1988). Usually first breeds at 3-4 years. Pair bond is not maintained outside breeding season, but bond may reform if both birds return to the same breeding territory. Some pairs may not breed in years of low prey abundance.

Ecology Comments

Some may remain on breeding territory all year; others may move irregularly in search of favorable foraging conditions. In Oregon, radio-tagged juveniles moved 9-31 km from nest over period of 1 year, adults moved 3-43 km during same period (see Johnsgard 1988). Predation by great horned owl was greatest known mortality factor in northern Minnesota and southeastern Manitoba (Duncan 1987).

Length

Weight

1298

Conservation Status

NatureServe Global Status Rank

Global Status Last Reviewed

1996-11-27

Global Status Last Changed

1996-11-27

Distribution

Conservation Status Map

Global Range

BREEDS: central Alaska to northern Ontario, south locally in mountains to California (vicinity of Yosemite), Idaho, Montana, Wyoming, central Saskatchewan, northern Minnesota, and south-central Ontario. WINTERS: generally throughout breeding range, wandering south irregularly to northern U.S. Also in Old World. Usually uncommon, but sometimes may be locally abundant.

ELEMENT_GLOBAL.2.100756