The Northern Spotted Owl and The Timber Industry
Northern spotted owls became a species of interest when environmentalists began calling for a change in logging practices. Learn the history of this controversy with Oregon Public Broadcasting's Timber Wars podcast. Episode 3 introduces northern spotted owls to the conversation, and features former primary investigator (and pioneer of spotted owl research) Eric Forsman.
Know your Pacific Northwestern Owls?
Learn more about things that go hoot in the night.
NORTHERN SPOTTED OWL
Strix occidentalis caurina
|
The northern spotted owl was listed as threatened under the Endangered Species Act in 1990. Major threats to spotted owls are timber harvest, wildfire, and barred owls. Providing adequate amounts of suitable forest cover to sustain the subspecies is a major component of the recovery plans and a driver in the basic reserve design and old forest restoration under the Northwest Forest Plan. Spotted owls use vocalization to establish and defend territories, find mates, and for communication between pairs. The typical territorial call is a stereotypic 4-note hoot. Other common calls are an ascending “series location” call and a contact “whistle” to communicate between pairs, and pair duets.
|
BARRED OWL
Strix varia
|
Barred owls are a congener to spotted owls that have expanded their range from eastern North America over the past 50 years to now encompass the entire range of the northern spotted owl. Barred owls are a slightly larger, more aggressive species, with more generalized diet and habitat requirements, and higher fecundity and survival compared to spotted owls. Barred owls use the distinctive 8-note hoot to establish and defend territories, find mates, and for communication between pairs. Other calls include wails and "caterwauling" duets between pairs.
|
GREAT HORNED OWL
Bubo virginianus
|
Great horned owls are large, powerful owls with the most widespread distribution of any owl species in North America. They occupy a wide range of forested habitats usually adjacent to wetlands, agricultural fields, meadows, or clear-cuts, as well as desert, grassland, and suburban areas. In the Pacific Northwest, great horned owls appear to avoid forest patches containing over 70% contiguous old growth. These owls are considered a primary predator of adult northern spotted owls. Great horned owls are diet generalists and opportunists, but their primary prey species are small mammals, mainly lagomorphs and rodents. Other prey include birds, insects, bats, and herpetofauna when available. Great horned owls have a deep, soft 4-note hoot, along with various squawks and grunts mainly given by females.
|
WESTERN SCREECH OWL
Megascops kennicottii
|
Western screech-owls are habitat generalists and will use a wide range of vegetation types as long as a cavities are available for nesting. Western screech-owls are slightly larger than both northern pygmy and northern saw-whet owls and take mainly mammalian prey. Recently, research has shown evidence of population declines in the Pacific Northwest, especially in British Columbia, presumably due to barred owl predation and competition. Typical sounds include a “bouncing ball” call that begins slowly and speeds up toward its end, and a double trill used to communicate between pairs. Females also produce a descending whinny call, likely to solicit feeding and copulation.
|
NORTHERN SAW-WHET OWL
Aegolius acadicus
|
Northern saw-whet owls are small owls with wide distribution across North America. In the west, they typically nest in dense coniferous forests, but roost and forage in deciduous patches in riparian areas, openings, and edges. Northern saw-whet owls primarily hunt mice and other small rodents. They are opportunistic foragers and unlike some other owl species, which show strong site fidelity, they may be nomadic, selecting new breeding locations based on prey abundance. Both male and female northern saw-whet owls produce rapidly repeated single-note hoots as their song, sometimes continued over an extended period. Other calls include wails, whistles, and a sharp descending “skew” bark.
|
NORTHERN PYGMY OWL
Glaucidium gnoma
|
The northern pygmy-owl, the smallest owl in the Pacific Northwest, is more diurnally active than any other species in this study. In its range, restricted to western North America, it is thought to use a variety of forest ages and types for breeding habitat, likely in part due to its generalist diet consisting of birds, small mammals, and insects. Though they can be quite common in parts of their range, there is limited information about this species as they are infrequently studied. The typical northern pygmy-owl song is a high, repeated hoot every 1-2 seconds, sometimes continued for several hours. At times, they begin vocalizing with a rapid trill before a series of typical hoots.
|