Bubo virginianus
(Great Horned Owl)


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

Physical Description:
18-25" (46-64 cm). Large owl with ear tufts set wide apart. Mottled gray-brown above with closely spaced, fine dark gray horizontal barring below. Conspicuous white throat bibClick word for definition below a tawny face.

Similar Species- Long-eared Owl

Song:
A deeply resonant hooting, usually uttered 5-6 times.

Distribution:
Breeds from western and central Alaska, east to southern Keewatin and Labrador, and south to southern South America. Winters generally throughout breeding range. Northernmost populations are partially migratory, wintering south to southern Canada and northern United States. Species is most common and widely distributed owl in Idaho.

Habitat:
Found in various moist or arid forested habitats, from lowland forests (deciduousClick word for definition or evergreen) to open temperate woodlands, including second-growth forests, swamps, orchards, riverine forests, brushy hillsides, and desert.

Diet:
Broad diet; eats mainly mammals (commonly mouse to rabbit size), and small to large birds (including hawks and waterfowl) but also amphibians, reptiles, and invertebrates. Idaho study found voles and deer mice were main food items. Parents provide about 300 g of food per day, per nestling.

Ecology:
Hunts from perch; captures prey on ground. CachesClick word for definition food. Utilizes abandoned stick nest in tree, cliff ledge, or man- made platform. Productivity peaks with snowshoe hare population in northern range. Size of home range varies seasonally and geographically. densityClick word for definition varies, but is usually about 1 pair/5-21 km2. Idaho study found density of 1.7 owls/10 km2; juvenile survival was 1.8/nest.

Reproduction:
Female incubatesClick word for definition 2-3 eggs for 26-35 days; male supplies food. Young leave nest at 4-5 wk, fly well at 9-10 wk, and are dependent on parents for several wk. Most yearlingClick word for definition females do not nest. Female may re-lay if first clutchClick word for definition is lost.

Conservation:
Element Code: ABNSB05010
Status: Protected nongame species
Global Rank: G5
State Rank: S5
National Rank: N5

Important State References:
Frounfelker, C.R. 1977. Prey selection of the great horned owl with reference to habitat and prey availability. M.S. Thesis, Univ. Idaho, Moscow. 62pp.


Photo by George Jameson, ©2002
Design by Ean Harker©1999, 2000.
Written by Jason Karl, 2000.