Strix nebulosa
(Great Gray Owl)

Order: Strigiformes
Order Description: Owls
Family: Strigidae
Family Description: Typical Owls

Physical Description:
24-33" (61-84 cm). Largest owl in North America. Large rounded head lacks ear tufts; long tail. Enormous pale facial disk patterned in concentric gray and brown circles; white crescent on throat with black chin spot; yellow eyes and bill. Mottled gray and brown above, gray and brown lengthwise streaking below.

Similar Species- Spotted and Barred Owls

Very deep whoo-hooo-hoo repeated in a series over eight or nine seconds.

Breeds from central Alaska to northern Ontario, and locally south in mountains to California (vicinity of Yosemite), Idaho, Montana, Wyoming, northern Minnesota, and portions of south-central Canada. Winters generally throughout breeding range.

Found in coniferous and hardwood forests, especially pine, spruce, paper birch, and poplar; also found in second growth, especially near water. In Idaho, found at lower elevations and in agricultural areas during winter, and in conifer forests in spring and summer, most commonly near extensive meadows.

Commonly eats pocket gophers and voles; may also eat other small mammals. In Idaho, owls nesting near clearcuts were found to have greater proportions of pocket gopher in diet.

Nests in broken-top snags or uses abandoned stick nest of other species, especially Goshawks. Hunts from perch; captures food on ground. 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. When nesting, may hunt day or night. In Oregon study, radio-tagged juveniles moved 9-31 km from nest over period of 1 yr; adults moved 3-43 km during same period. In Idaho study, home range per pair was found to be 2.6 km2. Predation by Great Horned Owl was greatest known mortalityClick word for definition factor in northern Minnesota and southeastern Manitoba study.

Lays eggs in March- June, depending on range. Mean date of first egg was 5 May in southern Idaho and northwestern Wyoming; egg-laying may be delayed in deep snow years. Female incubatesClick word for definition 2-5 eggs (3.3 in Idaho), for 28-29 days. Young leave nest at 3-4 wk (4 wk in Idaho and Wyoming), fly well at 5-6 wk (6 wk in Idaho and Wyoming), and become independent at about 4-5 mo. In Idaho study, mean s size was 3.0 young/pair.

Element Code: ABNSB12040
Status: Protected nongame species
Global Rank: G5
State Rank: S2
National Rank: N4

Important State References:
Franklin, A.B. 1988. Breeding biology of the Great Gray Owl in southeastern Idaho and northwestern Wyoming. Condor 90:689-696.

Design by Ean Harker©1999, 2000.
Written by Jason Karl, 2000.