Widely distributed through North America, the Barred Owl is a resident of deep forests, including swamps, riparian, and upland habitats. In the twentieth century, it has expanded its range north and west through the boreal forest, and south to northern California. Range expansion into the Pacific Northwest has brought the Barred Owl into contact with the closely related Spotted Owl (Strix occidentalis). The more aggressive Barred Owl has been known to displace and hybridize with the Spotted Owl, a further threat to that already endangered species.
Identified by its round head lacking ear tufts, brown eyes, and horizontal barring on its throat, the Barred Owl is about one-third smaller than the Great Gray Owl (S. nebulosa), slightly smaller than the Great Horned Owl (Bubo virginianus), and slightly larger than the Spotted Owl. A notable feature is its vocal repertoire. In addition to its distinctive 8-note hooting call (often rendered as "Who cooks for you? Who cooks for you all"), this owl projects a loud series of spectacular dueting vocalizations during courtship that sound like maniacal laughter.
Like the Spotted Owl, the Barred Owl is territorial throughout the year and monogamous, raising 1 brood a year. It is a true generalist predator, much like the Spotted and Great Horned owls, consuming a variety of birds up to the size of grouse; small mammals up to the size of rabbits; and amphibians, reptiles, and invertebrates.
Although the Barred Owl has been expanding its range in North America, concern exists for its populations in some areas. Relying on secondary tree cavities for nests, this owl is most often associated with large trees in old forests. Because of this, it is often used as an indicator species in the management of old forests. In the Pacific Northwest, however, the Barred Owl (unlike the Spotted Owl) readily inhabits mature second-growth forest.
Many aspects of the life history of this species have been well studied: e.g., its association with mature and old-growth forest ( Nicholls and Warner 1972 , Elody and Sloan 1985 , Haney 1997 , Mazur et al. 1998 ); its varied diet ( Marks et al. 1984 , Elderkin 1987 , Takats 1998 ); and territoriality and home range ( Nicholls and Warner 1972 , Elody and Sloan 1985 , Nicholls and Fuller 1987 , Hamer 1988 , Mazur et al. 1998 ). Breeding ecology and reproductive success, however, remain less well known, in part because its nests are hidden and inaccessible ( Devereux and Mosher 1984 , Elderkin 1987 , Postupalsky et al. 1997 ).