Bubo virginianus

Various forested habitats, moist or arid, deciduous or evergreen lowland forest to open temperate woodland, including second-growth forest, swamps, orchards, riverine forest, brushy hillsides, and desert. Very local in tropical lowlands (Hilty and Brown 1986).

Nest sites in different areas include: in trees in old or usurped nests of other birds (e.g., hawk, crow) or squirrel; tree cavities; stumps; rocky ledges; caves; in barns; and on artificial platforms. Usually in heaviest available timber in east; sites more diverse in arid west. Typically does not use same tree nest in successive years.

In Saskatchewan, productivity (number of young per nest and number of breeders) peaked with peak in snowshoe hare population (Houston 1987); declines in hare density resulted in increased owl dispersal and mortality (Houston and Francis 1995). Home range size varies seasonally and geographically. Breeding territories in southwest Yukon ranged from 230-883 hectares, averaging 483 hectares; home ranges of nonterritorial floaters overlapped the territorial pairs and averaged 725 hectares (Rohner 1997). Density varies in different areas, usually about 1 pair per 5-20 sq km.

Clutch size averages 2-3. Incubation lasts 26-35 days, mostly by female (male supplies food). Young leave nest at 4-5 weeks, fly well at 9-10 weeks, dependent on parents for several weeks. Most yearling females do not nest. Lost clutch may be replaced. Longevity record in the wild is at least 28 years.