Great Horned Owl Bubo virginianus This information was scanned from The Birds of British Columbia (Campbell et al.), Volume II, pages 360-361. Volumes I, II and III of The Birds of British Columbia can be ordered electronically at: orders@ubcpress.ubc.ca from UBC Press in Vancouver, British Columbia.

 

Range Breeds from the northern limit of trees in North America south throughout North, Central, and South America.

Status Common resident throughout the province, except in the Queen Charlotte Islands, where it is casual. Widespread breeder.

Status Change No change.

Nonbreeding The Great Horned Owl is a versatile, usually solitary species which is found in a wide variety of habitats throughout the province. There are 2 records for the Queen Charlotte Islands. Generally, populations appear to decrease northward through the province, and it is less common at higher elevations. It has been recorded from sea level to 2,040 m elevation. The Great Horned Owl is found in all types of timbered areas. It also frequents river valleys, lakeshores, agricultural and residential areas, swamps, fresh, brackish and marine marshes, and estuaries. Occasionally, it is found in cities, especially near golf courses or parks with adjacent woodlots. In British Columbia, the Great Horned Owl is considered nonmigratory, but dispersal and wandering does occur, especially during severe winters and shortages in food supply. For example, during the winter of 1926-27 a tremendous invasion of Great Horned Owls occurred on the south coast. During the 5 month period from October 1926 to January 1927, 287 Great Horned Owls were brought into Victoria taxidermists and sporting goods stores (Munro, J.A. 1928, 1929a). It is also one of the most numerous "found dead" or "road-killed" raptors in the province. On the extreme south mainland coast, D.J. Wilson (pers. comm.) reported that, in 1982 and 1983, it was the second most common raptor (behind Barn Owl) brought in dead to the Wildlife Branch office in Surrey.

Breeding Nests Eggs Young The Great Horned Owl breeds throughout the province except on the Queen Charlotte Islands, almost anywhere there are groups of small and large trees. It may be found in dense forests, open woodlands bordering lakes and marshes, and along fence rows. It also breeds in holes and crevices in cliffs, clay banks, and man-made structures. Nests have been found from sea level to 1,220 m elevation.

Nests:  Most nests (98%; n=97) were situated in natural sites, including coniferous or deciduous woods (75%), and cliffs (20%). In wooded areas, most (89%; n=75) were open tree nests, 8% were in the top of broken snags, and 3% were in large tree cavities. Nineteen nests were situated in crevices and cavities in rock cliffs and clay banks. In addition, 2 nests were found on metal bridges, and 1 was situated on the ground. Of the 75 tree nests, 57% were in coniferous trees including Douglas-fir (37%), white spruce (12%), ponderosa pine, grand fir, western redcedar, and Norway spruce. The remaining tree nests were found in deciduous trees including black cottonwood (21%), trembling aspen (9%), red alder, paper birch, and willow. Open tree nests of the Great Horned Owl were generally in old nests of other large birds or among parasitic vegetative growths. Nests of other birds (n=47) included Red-tailed Hawk (43%), American and Northwestern crows (Corvus brachyrhynchos and C. caurinus; 19%), Great Blue Heron (11%), Bald Eagle (8%), Common Raven (Corvus corax; 6% -- all in cliffs), Cooper's Hawk, and Northern Goshawk. Three nests were found among witch's broom. All but 7 nests were positioned in the crotches of branches next to the trunk.  Heights for 67 tree nests ranged from 1.5 to 34 m, with 54% recorded between 7.6 and 14 m. Eggs: Dates for 38 clutches ranged from 15 February to 20 May, with 50% recorded between 24 February and 18 March. Sizes for 35 clutches ranged from 1 to 4 eggs (1E-3, 2E-25, 3E-5, 4E-2), with 71% having 2 eggs. Incubation periods for 3 clutches in British Columbia ranged from 30 to 32 days which is within the range reported by Gilkey et al. (1944). Young: Dates for 203 broods ranged from 23 March to 10 September, with 51% recorded between 20 April and 1 June. Brood size ranged from 1 to 4 young (1Y-64, 2Y-110, 3Y-26, 4Y-3) with 54% having 2 young. Fledging period is 31 to 35 days but young do not fly well until 63 to 70 days (Harrison, C. 1978).

Remarks Three of the ten North American subspecies of the Great Horned Owl are found in British Columbia. Bubo virginianus subarcticus breeds in the Peace Lowlands, B. v. Iagophonus in the interior, and B. v. saturates along the coast. See Godfrey (1986) for additional information on descriptions of the races and taxonomic relationships.