Northern Spotted Owl
The Northern Spotted Owl evolved for thousands of years in the old-growth forests of the Pacific Northwest.
Ministry of Environment, Lands and Parks Logging and other forms of land servation effort which has begun. development are continuing within the Northern Spotted Owl range in British What do they look like? Columbia. Only a few tracts of low ele- he Northern Spotted Owl (Strix occi- Why are Northern Spotted vation old-growth are protected in dentalis caurina) is a fairly large, Owls at risk? parks. Biologists are working hard to brown owl, 40 to 48 centimetres he Northern Spotted Owl has a very ensure that logging practices are car- T long, with a puffy round head and no restricted range within British ried out in such a way that Northern ear tufts. Of the 14 species of owls that Columbia. It is at risk in this Spotted Owls will continue to exist. nest in British Columbia, only the Great T province because much of its habitat Gray and Great Horned are noticeably has been adversely affected by logging or What is their status? larger. Female Northern Spotted Owls lost due to land development. The he total known population of are slightly larger than males, but both Northern Spotted Owl – the subspecies Northern Spotted Owls is only 4000 have similar colouring and markings. of Spotted Owl found on the Pacific adult pairs. British Columbia is The chocolate to chestnut brown feath- coast – evolved for thousands of years in T estimated to have fewer than 100 ers of the head, neck, back and under- the old-growth forests that dominated pairs. The Northern Spotted Owl has parts have many circular or irregular this area. It is dependent on the features been placed on British Columbia’s white spots, for which this attractive owl of old-growth forest stands for its nest Red List because of its small and is named. The Northern Spotted Owl sites, roosts, cover and prey. vulnerable population and continuing has large, round facial discs with dark The kinds of forest preferred by the habitat loss. The Red List includes outer rims, dark brown eyes and a Northern Spotted Owl are also those those species being considered for yellowish-green bill. of greatest value to the forest industry. legal designation as Endangered or In British Columbia, the Northern Little old-growth remains in the North- Threatened under the British Colum- Spotted Owl is most likely to be con- ern Spotted Owl’s range within Wash- bia Wildlife Act. The Committee on fused with its close relative, the slight- ington and Oregon, and populations the Status of Endangered Wildlife in ly larger Barred Owl. These species are there are declining. The total known Canada () has designated best differentiated by their under- range of the Northern Spotted Owl in the Northern Spotted Owl as Endan- parts. The Northern Spotted Owl is British Columbia is approxi- gered in Canada, brown with oval white spots on the mately two percent of the has meaning that the body feathers and white horizontal provincial area. Within that species is threat- bars on the chest. The Barred Owl area, only about 30 percent of designated the ened with immi- has vertical brown streaks on a whitish the original low-elevation old- Northern nent extir-pation background and no white spots. growth remains and the total throughout all Like other owls, the Northern Spot- owl population is estimated to Spotted Owl as or a sig-nificant ted Owl has fluffy plumage that allows be about 100 breeding pairs. Endangered in portion of its nearly soundless flight; sharply curved The size of pre-logging owl Canadian range. talons and a hooked bill to catch and populations is not known, but it Canada. In 1988, the tear apart prey; eyes adapted for night is very likely the numbers were Northern Spotted vision; and very acute hearing. higher than at present. In Owl was listed as British Columbia, owl habitat is Endangered in Wash-ington State and What makes them unique? becoming fragmented. The widely Threatened in Oregon. In 1990, it was he owls as a whole are a unique spaced populations are vulnerable to designated as Threatened throughout its group – phantom-like night hunters severe natural events that can cause entire range in the United States under with eyes and ears that are sensitive local extinction. When the habitat was the U.S. Endangered Species Act. T to the dimmest light and faintest rus- continuous, areas of local extinction The Northern Spotted Owl is one tle. Several of British Columbia’s 14 breed- could be re-populated by owls from of British Columbia’s rarest birds, ing owl species occur in coastal Pacific adjacent areas. This is less feasible when although it may never have been forests, but none seem to be so at home the remaining habitat patches are sepa- widespread or abundant in this there as the Northern Spotted Owl and rated by large areas of clear-cut land, province. Its status is precarious but no others are restricted to that zone. urban development or farm fields. may improve with the concerted con- Though armed with a raptorial bill and talons like the hawks mental in protecting and falcons, the style of other less-known the Northern Spotted wildlife species that have Owl is not to attack with similar habitat require- lightning stoop and ments. bruising force, but rather to sit patiently on a perch How do they and wait. This strategy is reproduce? suited to foraging in orthern Spotted Owls dense forests at night. are monogamous and Not powerful flyers, these adult pairs have weak- owls employ a few flaps Nly defended, overlap- and a silent glide to cap- ping home ranges of ture prey from tree about 32 square kilome- branches or the forest tres in size. They occupy floor. They are also adept these territories for long at walking and climbing, periods, probably for life. useful traits in their clut- The territories must be tered forest habitat. If on large enough to sustain an the first try they miss a adequate population of mammal on the ground, Northern Flying Squirrels, they often run after it on their principal prey. fully extended legs, with In fall and winter the wings widespread for adults lead a mostly soli- balance. They exhibit a tary existence, but in rolling gait when they late February or March walk on the ground, or – one to two months along a tree limb to cache before egg-laying – the prey or bring food to resident male and their young. female begin to roost Vocal communication is important known as the “four-note location call,” together near the nest site. At this for keeping in touch at night and the has been described as hoo—hoo- time they begin to call almost every Northern Spotted Owl has an array of hoo—hooo. This call is the one most night, particularly at dusk and dawn. at least 13 calls, including hoots, frequently imitated by biologists, Copulation sessions begin two to barks, whistles and chitters. These are either vocally or with a tape recorder, three weeks before egg-laying and associated with mating, territorial when censusing these owls at night. continue until a few days after the last advertisement, approach of predators, Thinking a stranger has invaded their egg is laid. The male brings food contact between mates, begging for territory, the resident owls respond nightly to his nest-bound mate dur- food, and other activities in the night- and reveal their presence. ing the laying, incubation and early ly life of the owls. This species is Being so closely tied to old-growth brood-rearing stages, and roosts near unusual in having the ability to learn forest, the Northern Spotted Owl is a the nest by day. the calls of its Northern Spotted Owl valuable barometer of the integrity Nests are centrally located within a neighbours and make fine adjust- and health of such ecosystems. It has pair’s home range, usually near streams ments to its own call to imitate them. been more intensively studied than or springs that are thought to be Recognition of neighbours’ calls any other owl and is one of the best important for bathing and drinking. serves to limit territorial disputes. understood old-growth residents. Along the Pacific coast, Northern Spot- Females can be distinguished from Knowledge of how individuals, pairs ted Owl nests are almost always males by the higher pitch of their and populations of Northern Spotted 10 to 50 metres above ground in large hooting calls. The best known nesting Owls respond to various forest coniferous trees in old-growth stands. season call, made by both sexes and management measures can be instru- The typical nest is in an open-ended, “stovepipe” cavity created by breakage fledge – about 35 days after hatching. Present range of the Spotted Owl in Canada at the top of a tree; the branches of sec- In British Columbia, egg laying proba- and the United States ondary stems or neighbouring trees bly occurs in early April, incubation in provide cover above the cavity. Alter- April and early May, and fledging natively, a cavity in the side of a tree from late May to early July. may be used. These owls are some- Young Northern Spotted Owls are times platform nesters – using either poor flyers when they leave the nest, abandoned stick nests made often falling to the ground and then by hawks, woodrats or squirrels, or climbing trees or shrubs for safety. dense, misshapen clusters of mistle- Researchers in Oregon found that toe-infected branches known as several owlets fell “witches’ brooms.” Being large The Northern from platform in diameter and prone to break- nests premature- age, heart rot and dwarf mistle- Spotted Owl ly, at only 15 to toe infection, old trees provide is a valuable 25 days of age, nest sites that are lacking in sec- and were killed ond-growth forest. barometer by the fall or by Northern Spotted Owls never of the predators. This build or even repair their nests; was not observed the female merely scrapes out a integrity and at cavity nests, Northern Spotted Owl California Spotted Owl hollow in the needles, twigs and which appear to health of Mexican Spotted Owl rotten wood that are already be more secure present. There she lays usually old-growth brood-rearing two, sometimes three or rarely ecosystems. sites. Fledged sib- their nest sites but don’t lay any four elliptical white eggs at lings stay togeth- eggs. Usually about 80 percent of three-day intervals. Incubation, er near the nest nesting attempts result in successful beginning soon after the first egg is and are fed by their parents until late fledging of young. The causes of egg laid, is entirely by the female and takes August or early September, but start and nestling losses include occasion- about 30 days. During incubation, the catching some of their own food by al abandonment by adults, nest female only leaves the nest for occa- late summer. In autumn they dis- destruction due to predation or col- sional 10 to 20 minute periods at night perse randomly away from the nest- lapse of the tree, unexplained death to regurgitate pellets, defecate or ing area and must fend for them- of owlets in the nest, and premature preen. For the first 10 days after selves. Juveniles often find territories departure of owlets from the nest. the owlets hatch, within 5 to 20 About 35 percent of the fledged she broods them km of their natal young die by late August, a major Present range of the Spotted Owl in almost constant- British Columbia area, but may cause being predation by ravens and ly. After that she disperse 50 km by raptors like the Great Horned begins to make or more during Owl, Red-tailed Hawk and Northern short forays to their first year. Goshawk. catch prey, but Pairs normal- Northern Spotted Owls may roosts with the ly nest in the breed when one or two years old, but young by day, same area for most young are produced by females until they are several years, al- that are three or more years old. nearly ready to though some- They are long-lived birds, as shown Kamloops leave the nest. times they have by records of individuals surviving The pure white to switch trees at least 25 years in captivity and 16 down of the when the old to 17 years in the wild. Such longevi- newly hatched owlets is mostly one dies, falls or rots away. In Oregon, ty is typical of species with a low replaced by their first or juvenile about 60 percent of the adult pairs reproductive rate and a high rate of plumage by the time they are ready to nest each year; the rest just hold down adult survival. What do they eat? fir and Englemann Spruce–Sub- argely inactive by day, the alpine Fir zones. The characteris- Northern Spotted Owl is a tics of their preferred habitat superb night-hunter, gliding include numerous large trees and Lswiftly and quietly from a perch snags with broken tops, large cavi- to pounce on its unsuspecting prey. ties or mistletoe-infected limbs Most hunting occurs during the to provide nest sites; lots of logs first two hours after sunset and and woody debris which encour- again just before dawn. Being noc- age the presence of small mam- turnal, the owl must satisfy its mal prey; and a canopy that is dietary needs with animals that are open enough to allow owls to fly also active at night. It specialises within and beneath it, and is on small mammals, which com- sufficiently multi-layered to pro- . prise 90 to 95 percent of its diet. Jared Hobbs photo vide roosting and foraging Predominant food items vary perches at a variety of heights. throughout the range of the These habitat features are most Northern Spotted Owl. In the wet Spotted Owls in areas with a mixture often found within old-growth and coastal regions from British Colum- of logged land and old-growth forest mature forests. Although owls have bia to Oregon the main prey is the have shown they have a strong prefer- been observed using younger forests Northern Flying Squirrel, which is ence for foraging in old-growth in drier parts of their range, these most abundant in old-growth forests. stands. Areas that have been clearcut have generally been forests that con- Additional prey include the Deer or burned within the previous 20 tained some structural characteristics Mouse and other mammals like wood- years are rarely used for hunting. of old-growth – such as large trees, rats, voles, moles and hares. In the snags and downed logs – left behind more inland and drier parts of the Where do they live? after fire, wind or selective logging owl’s range, woodrats tend to be orthern Spotted Owls live in west- removed the majority of the trees. more important than flying squirrels. ern North America, from southern Surveys in British Columbia have An intensive study in Oregon deter- British Columbia to central Mexico. identified breeding pairs in the Capi- mined that Northern Spotted Owls NThree subspecies or geographic lano, Seymour and Coquitlam river killed 31 kinds of mammals, includ- races have been described. The Mexican watersheds near Vancouver; the Lil- ing snowshoe hares. Birds comprise Spotted Owl inhabits mountainous ter- looet River watershed; the Fraser River only about five percent of the owl’s rain from Colorado southward into Mex- area south of Lytton; the upper diet. Large insects and the occasional ico. The California Spotted Owl is found Chehalis and Chilliwack river water- reptile are also eaten. in the dry forests and canyons of interior sheds; around Boston Bar, Hope Prey are caught on the ground or in and south-coastal California. The North- and the Skagit River; and in Manning trees. The owls seize their victims with ern Spotted Owl is restricted to the tem- Park and the upper Similkameen. This their talons and use their beak to kill perate coniferous forests from northern species may also occur slightly beyond them by crushing their skull or break- California to extreme southwestern the known range, but further surveys ing their neck. They usually eat mam- British Columbia. The range in British are needed to confirm or disprove this. mals headfirst, a common practice of Columbia is very small: north to the Northern Spotted Owls are now owls and hawks. Small mice may be vicinity of the Elaho River, Pemberton absent from the heavily settled Greater swallowed whole, but most mammals and Carpenter Lake, and east to the Vancouver–Fraser Valley area and are dismembered and the stomachs Fraser Canyon, the Coquihalla and scarce in extensively logged valleys like and tails discarded. Northern Spotted Manning Park. They do not occur on the Squamish-Pemberton corridor. Owls regularly cache or store excess Vancouver Island. food and retrieve it later. Cached food In British Columbia, Northern What can we do? is wedged securely in place with the Spotted Owls have been found from esearch on the Northern Spotted beak, either in trees or on the ground sea level to 1370 metres elevation with- Owl has documented its depen- beside a log, tree or large rock. in the Coastal Western Hemlock, dence on coastal old-growth, the Studies of radio-tagged Northern Mountain Hemlock, Interior Douglas- Rmost commercially valuable forest stands in North America. Outside of parks, the majority of old-growth in this owl’s range has already been logged. The remainder is in some jeopardy and owl populations are declining. Although more inventory and research is always desirable, we already have clear evidence that this owl can survive only if reserves containing significant amounts of mature or old-growth forest are provid- ed for it. Such reserves will, of course, also benefit many other organisms. In 1994, the Canadian Spotted Owl Recovery Team completed a recovery plan for the species which included a variety of options addressing both owl - conservation and economic impacts. - . . Dave Dunbar photo A joint Ministry of Environment, Jared Hobbs photo Lands and Parks and Ministry of Forests team then developed a man- agement plan, released in 1997. This vulnerable and intriguing bird. Half plan allows for permanent protection the people in British Columbia share of some key habitat through the Pro- the Lower Mainland region with the tected Area Strategy and for the estab- Northern Spotted Owl. Good neigh- lishment of Special Resource Manage- bours should be concerned about what ment Zones, each maintaining 2 to 13 is happening next door. As goes the breeding pairs of owls, in the Chilli- Northern Spotted Owl, so will go other wack and Squamish Forest Districts. wildlife species, and we will be the Forest practices in these zones will be poorer for losing them. directed towards creating, enhancing or maintaining 67 percent of the area of these zones in suitable Northern Spotted Owl habitat conditions. Owls . Dave Dunbar photo found outside the zones should still receive some protection through the biodiversity guidelines of the Forest , : Practices Code. The probability of Wildlife Branch maintaining or even slightly increas- Ministry of Environment, Lands and Parks ing existing population levels with PO Box 9374, Stn Prov Govt these management practices is esti- Victoria, British Columbia V8W 9M4 mated at 60 percent. The public can help Northern Spot- ted Owls by supporting endangered Forest Renewal British Columbia species programs and by encour-aging government to place a high --- priority on maintaining and recovering . , endangered and threatened species and their habitats. Naturalists are urged to become familiar with Northern Spotted Owl calls and to report sightings of this Printed in British Columbia on recycled paper with vegetable inks ..