Characteristics
The northern spotted owl is a medium sized owl of about 40 cm in height and a wingspan of 1.0 m. Females are larger than males and weigh about 700 grams, whereas males only weigh about 600 grams. They are dark or chocolate brown with white spots on the back of the head and neck - which is where the name "spotted" comes from. The breast is white with brown markings, the eyes are dark brown, and the beak and feet are grey.
Habitat and Geography
The northern spotted owl is a sub-species of the spotted owl, occupying the northern-most portion of the range for the species. They are an "umbrella" species, meaning that their presence in an area is an indicator of the health of the entire ecosystem. They live in old-growth forests where the trees, mostly Douglas fir or western red cedar, are 100-300 years old and stand 19 meters tall. The northern spotted owl is found from the Pemberton-Lillooet area down through Oregon on the west-side of the Cascade Mountains. They nest in "snags" - the cavities or chimneys that remain at the top of a large tree stump after the top has fallen off.
Life History
Northern spotted owls typically live to be about 8 or 9 years of age in the wild - in captivity that age extends to 23 or 24 years. They are monogamous and mate for life once a bond is formed. Males reach sexual maturity and can produce offspring as early as one year of age. Generally, females are slower to mature and can reach sexual maturity as young as one year and as old as seven years.
In the wild, breeding season begins in the early spring and 1-3 eggs are laid in April or May. The female sits on the eggs exclusively, relying on her mate for food. She only leaves the nest for short periods of time to defecate and copulate with her mate. Eggs incubate for 32 days before hatching after approximately 80 hours. Chicks remain in the nest with mom for 4-5 weeks before fledging.
Diet
In the wild spotted owls eat about 80% northern flying squirrel. The other 20% of the diet is made up of wood rats and other small rodents. They do not regularly eat insects, birds or reptiles and amphibians, although it is possible.
Threats
The northern spotted owl has become endangered for 3 mains reasons:
1: Habitat Loss
The amount of old growth forest habitat available for the northern spotted owl has decreased significantly over the past 100 years. Currently there is approximately 300,000 hectares of suitable habitat protected by the Province of BC for future release of spotted owls. More info can be found here.
2. Habitat Fragmentation
The remaining habitat for the spotted owl has been severely fragmented, which creates a barrier for dispersing juveniles. Focusing on ways to connect fragmented areas of old growth forests will be key in the success of an introduced owl establishing a territory.
3. Invasion of the barred owl
The barred owl is originally from the east side of North America and over the last 100 years or so has made it across the prairies and over the Rocky Mountains. It was previously unable to cross the Prairies as the habitat was not suitable, but human settlement has created habitable "islands" in the form of cities, parks, even trees in backyards. The barred owl is morphologically very similar to the spotted owl, but is more aggressive and adaptable. They will live anywhere and eat anything, and out-compete the spotted owl for resources when sharing the same habitat.
Population and Conservation
Provincial biologists estimate that there are currently less than six wild northern spotted owls remaining in Canada as of November 2020. They are provincially Red-Listed and federally recognized as critically endangered. There are greater numbers in Washington and Oregon, but these populations are decreasing. The spotted owl is internationally recognized as "threatened", which combines the population estimates for all three subspecies: California, Mexican, and northern spotted owl.
The NSOBP is the only one breeding the northern spotted owl and we are the only facility to house resident spotted owls.
Field biologists monitor the wild population and remove barred owls from spotted owl habitat. Studies have recently shown that spotted owls will return to habitat after barred owls have been removed and translocated barred owls rarely return to their capture site.
Currently the Province of BC has protected 300,000 hectares of old-growth forest for the spotted owl. This provides enough space for approximately 250 individuals. Information about the habitat can be found at the Province of BC's Stewardship Baseline Objectives Tool for Spotted Owls found here.