Spotted Owl caurina subspecies (Strix occidentalis caurina): amended recovery strategy proposed 2024

Official title: Amended Recovery Strategy for the Spotted Owl caurina subspecies (Strix occidentalis caurina) in Canada proposed 2024

Species at Risk Act
Recovery Strategy Series

Preface

The federal, provincial, and territorial government signatories under the Accord for the Protection of Species at Risk (1996)^{Footnote 2} agreed to establish complementary legislation and programs that provide for effective protection of species at risk throughout Canada. Under the Species at Risk Act (S.C. 2002, c.29) (SARA), the federal competent ministers are responsible for the preparation of recovery strategies for listed Extirpated, Endangered, and Threatened species and are required to report on progress within five years after the publication of the final document on the Species at Risk Public Registry.

The “Recovery Strategy for the Northern Spotted Owl (Strix occidentalis caurina) in British Columbia” (Chutter et al. 2004), and two addendums prepared by the Canadian Spotted Owl Recovery Team and Environment Canada, respectively, was originally adopted as the federal recovery strategy for the Spotted Owl caurina subspecies, and posted on the Species at Risk Public registry in October 2006 (Environment Canada 2006). An amendment was required because the identification of critical habitat in the 2006 version of the recovery strategy was insufficient to meet the population and distribution objectives, and a schedule of studies required to complete the identification of critical habitat was included.

This Amended Recovery Strategy for the Spotted Owl caurina subspecies (Strix occidentalis caurina) in Canada includes updated information on the species population, distribution, and threats, and a refined population and distribution objective that addresses the reasons behind the at-risk status of the species, includes short-term recovery statements, and has a clear timeline goal in accordance with the Policy on Survival and Recovery (Government of Canada 2020). The previous objectives from 2006 were developed before these guidelines were in place. The identification of critical habitat has also been updated to include new information and modeling, informed by the updated population and distribution objective.

The Minister of Environment and Climate Change is the competent minister under SARA for the Spotted Owl caurina subspecies and has prepared this amended recovery strategy, as per section 37 of SARA. To the extent possible, it has been prepared in cooperation with the province of British Columbia, as per section 39(1) of SARA.

Success in the recovery of this species depends on the commitment and cooperation of many different constituencies that will be involved in implementing the directions set out in this strategy and will not be achieved by Environment and Climate Change Canada or any other jurisdiction alone. All Canadians are invited to join in supporting and implementing this strategy for the benefit of the Spotted Owl caurina subspecies and Canadian society as a whole.

This recovery strategy will be followed by one or more action plans that will provide information on recovery measures to be taken by Environment and Climate Change Canada and other jurisdictions and/or organizations involved in the conservation of the species. Implementation of this strategy is subject to appropriations, priorities, and budgetary constraints of the participating jurisdictions and organizations.

The recovery strategy sets the strategic direction to arrest or reverse the decline of the species, including identification of critical habitat to the extent possible. It provides all Canadians with information to help take action on species conservation. When critical habitat is identified, either in a recovery strategy or an action plan, SARA provides a legal framework that enables the protection of that critical habitat.

In the case of critical habitat identified for terrestrial species, including migratory birds, SARA requires that critical habitat identified in a federal protected area^{Footnote 3} be described in the Canada Gazette within 90 days after the recovery strategy or action plan that identified the critical habitat is included in the public registry. A prohibition against destruction of critical habitat under ss. 58(1) will apply 90 days after the description of the critical habitat is published in the Canada Gazette.

For critical habitat located on federal lands that are not a federal protected area, as in SARA ss. 58(2), the competent minister must make an order applying the ss. 58(1) prohibition against destruction of critical habitat if it is not already legally protected by a provision in, or measure under, SARA or any other Act of Parliament. If the competent minister does not make the order, a statement must be included on the Species at Risk Public Registry setting out how the critical habitat, or portions of it are legally protected on those federal lands.

If there are portions of critical habitat of a migratory bird to which the following applies:

1. habitat to which the Migratory Birds Convention Act, 1994 applies, and
2. not on federal land, within the exclusive economic zone, or on the continental shelf of Canada, and
3. not within a migratory bird sanctuary

SARA requires that the Minister recommend that the Governor in Council make an order to prohibit destruction of critical habitat, if the competent minister forms the opinion that there are no provisions in, or measures under, SARA or other Acts of Parliament that legally protect them. If the competent minister does not make the recommendation, a statement must be included on the Public Registry setting out how those portions of critical habitat for the migratory bird are legally protected. Spotted Owl is not a migratory bird under the Migratory Birds Convention Act, 1994.

For any part of critical habitat located on non-federal lands, if the competent minister forms the opinion that any portion of critical habitat is not protected by provisions in or measures under SARA or other Acts of Parliament, or the laws of the province or territory, SARA requires that the Minister recommend that the Governor in Council make an order to prohibit destruction of critical habitat. The discretion to protect critical habitat on non-federal lands that is not otherwise protected rests with the Governor in Council.

Acknowledgments

Many people are to be acknowledged for their involvement in the federal recovery planning process for the Spotted Owl caurina subspecies. Development of this recovery strategy was coordinated by Megan Harrison and Kella Sadler (Environment and Climate Change Canada, Canadian Wildlife Service - Pacific Region (ECCC-CWS-PAC). Greg Rickbeil, Danielle Yu, and Leon McCarthy (ECCC-CWS-PAC) provided geospatial modelling and mapping support. This amended recovery document borrows significantly from the original Recovery Strategy for the Northern Spotted Owl (Strix occidentalis caurina) in British Columbia (Chutter et al. 2004), which was adopted as part of the federal Recovery Strategy for the species in 2006. All those involved in the development of that original document are gratefully acknowledged. In addition, thanks are owed to Jared Hobbs and Glenn Sutherland (independent experts); Joe Buchanan (Washington Department of Fish and Wildlife); Ian Blackburn, Nicola Bickerton, Joel Gillis (B.C. Ministry of Water, Land and Resource Stewardship [WLRS]); and Louise Waterhouse (B.C. Ministry of Forests) who provided expert input into this updated document. Helpful review comments were also provided by numerous individuals from the federal and provincial governments, First Nations, and members of the public, on earlier versions of this document including a proposed version posted on the Species at Risk Public Registry in January 2023.

Executive summary

This document builds on the original Recovery Strategy for the Northern Spotted Owl (Strix occidentalis caurina) in British Columbia (Chutter et al. 2004), which was adopted as part of the federal Recovery Strategy for the species in 2006. The 2006 document contains more comprehensive information on the species’ life history and early recovery measures, so it should be consulted for background. Detailed planning/strategy documents published since the original recovery strategy (for example, Sutherland et al. 2007; Fenger et al. 2007) should also be consulted for additional background.

The Spotted Owl caurina subspecies (henceforth, the Spotted Owl) is a medium-sized owl with dark brown plumage patterned by small pale spots over most of the body. The species was first assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as Endangered in 1986. Its status was re–assessed and re-confirmed in 1999, 2000, and 2008. The species was designated as Endangered due to catastrophic population decline (driven by habitat loss and fragmentation and competition from the closely-related Barred Owl [Strix varia]), severely depressed population size, and continued vulnerability to ongoing threats.

The Spotted Owl once occurred throughout mixed-coniferous old-growth forests in southwestern British Columbia (B.C.) and may have numbered as many as 500 pairs prior to the impacts of significant human activity. Its historical range spans three ecological sub-regions that differ in their mean annual precipitation and corresponding habitat characteristics: the wet ‘Maritime’, moist ‘Sub-maritime’, and dry ‘Continental’. Both the population and the distribution of the Spotted Owl have declined precipitously from historical estimates, with only one wild-born individual detected in its natural habitat in 2022. As of September 2023, there are 37 known Spotted Owls in British Columbia: the wild-born individual, two owls released from a captive breeding facility into the wild in July 2023, and 34 owls in a captive breeding facility.

Throughout its range, the Spotted Owl is strongly associated with mixed-coniferous forests that are characterized by: an uneven-aged cohort of trees; a multi-layered, relatively closed canopy; numerous large trees with broken tops, deformed limbs, and large cavities; and numerous large snags and accumulations of logs and downed woody debris. The full set of features and attributes needed to support all life functions (nesting, roosting, foraging, and safe movement/dispersal) are most typically associated with old-growth forests. Mature forests more often contain only a subset of these attributes, which may for example support foraging and safe movement/dispersal, but not other life functions such as nesting.

The primary threats to the Spotted Owl in B.C. include: problematic native species (that is, competition from Barred Owls), logging and wood harvesting, roads and railroads (including logging roads), and fire and fire suppression.

The population and distribution objective is to recover the Spotted Owl in Canada by restoring a stable population of at least 250 mature individuals distributed within a connected network of habitat representative of all three sub-regions within the species’ historical Canadian range, and linked to the larger population in the U.S.A.

Recognizing that the population and distribution objective will take >50 years to achieve, the following short-term recovery statements toward meeting the population and distribution objective have been established:

1. immediately cease human-caused destruction of biophysical attributes of old-growth forests as outlined in section 7.2 of this document and mitigate all other human-caused threats as outlined in section 4.1 that would cause loss of habitat needed for recovery (that is, the critical habitat)
2. re-introduce at least 50^{Footnote 4} captive-bred Spotted Owls to the wild by 2033, with at least 10 released individuals surviving to become resident adults
3. complete annual Barred Owl surveillance at sites occupied by Spotted Owl and/or where reintroductions are planned and remove all Barred Owls that are detected

Broad strategies and general approaches toward addressing the primary threats to the survival and recovery of the species, as well as key knowledge gaps, are presented in section 6. Successful implementation of these broad strategies and approaches will be required for the population and distribution objective to be met.

Critical habitat has been identified to the extent possible, based on the best available information for the Spotted Owl. It is recognized that the acoustic critical habitat^{Footnote 5} identified is insufficient to achieve the population and distribution objectives for the species. A schedule of studies (Section 7.2) has been developed to provide the information necessary to complete the identification of acoustic critical habitat that will be sufficient to meet population and distribution objectives.

Three performance indicators were developed to measure progress towards meeting the population and distribution objective. One or more action plans for the Spotted Owl will be posted on the Species at Risk Public Registry within five years of the final posting of the recovery strategy.

Recovery feasibility summary

Based on the following three criteria that Environment and Climate Change Canada uses to establish recovery feasibility, it is considered to be biologically and technically feasible to recover the Spotted Owl in Canada (see Species at Risk Policy on Recovery and Survival [Environment and Climate Change Canada 2021]), although there are some significant uncertainties associated with this determination. In keeping with the Guidelines on Characterizing Recovery and Developing Population and Distribution Objectives under the Species at Risk Policy on Recovery and Survival (Environment and Climate Change Canada 2021), where there is a range of uncertainty associated with the full extent of improvements that are biologically and technically feasible, the determination defaults to the upper bound of what is considered to be within the scope of biological and technical feasibility.

1. Survival characteristics: Can survival characteristics be addressed to the extent that the species is no longer at significantly greater risk of extinction or extirpation as a result of human activity?

Yes: The Spotted Owl is currently assessed as Endangered on the basis of four key survival characteristics: (i) resilience (D1 COSEWIC quantitative criteria^{Footnote 6}) – its wild population is estimated to be small (well below the 250-individual threshold for Endangered status) and is in decline; (ii) redundancy and connectivity (linked with COSEWIC B2ab indicators) – its habitat and associated distribution is in decline and fragmented (iii) stability (linked with COSEWIC A2ac, C1+2a, and E indicators) - there is an ongoing decline in the number of mature individuals and area/quality of habitat, and a quantitative analysis showing high probability of extirpation, and (iv) continuing impacts caused by ongoing human-caused threats.

Resilience:

Prior to impacts from human activity (that is, in its natural condition), the Spotted Owl population in Canada may have been as many as 500 mature individuals (Blackburn et al. 2002). This small population size would have meant the species’ persistence was somewhat precarious even in its natural condition (for example, would still be assessed as Threatened under the COSEWIC D1 quantitative criteria, which apply to a species with <1000 mature individuals). However, the results of human activity have put the species at a significantly greater risk of extirpation, such that it is now assessed as Endangered on the D1 indicator (that is, population below 250-individuals). For recovery to be considered feasible, it must be biologically and technically feasible to improve the resilience of the Spotted Owl such that it exceeds the 250-individual D1 threshold associated with Endangered status, and thus returns to a status of Threatened (on the basis of D1 criteria).

As of mid-2022, only one wild-born female owl may remain in its natural habitat (Government of B.C. 2022). The Spotted Owl is known to suppress its calling in the presence of the closely-related competitor, the Barred Owl (Strix varia; Kelly et. al 2003; Crozier et al. 2006; Van Lanen et al. 2011; Yackulic et al. 2019) and Barred Owls have been detected at all 10 sites surveyed in 2020 that were previously occupied by Spotted Owls, so it is possible that some owls are present at surveyed sites but are going undetected by standard call-playback survey methods.

Comprehensive, range-wide surveys have also not been undertaken in recent years, so some owls may still exist in un-surveyed areas, although given known rates of juvenile survivorship and recruitment this seems unlikely. However, even accounting for uncertainties about undetected individuals, the wild population is clearly extremely small and would have correspondingly low genetic diversity. The population is apparently incapable of recovering on its own, so resilience cannot be addressed without the reintroduction of owls from a captive breeding program (Fenger et al. 2007).

A Spotted Owl captive breeding and reintroduction program has been in operation in B.C. since 2007 (Northern Spotted Owl Breeding Program n.d., Government of B.C. 2021). The first release occurred in August 2022, when three captive-bred male owls were released into two Wildlife Habitat Areas; one was later found injured and returned to captivity, and the other two died of unknown causes (Government of B.C. 2023a). In late June 2023, the previously injured captive owl and one additional male were released (Government of B.C. 2023b). As of September 2023, there are 27 adults and seven chicks born in 2023 in captivity (Government of BC representatives, pers. comm. 2023). IBased on minimum targets^{Footnote 7} of releasing ~4 individuals/year from 2023 to 2024, ~9 individuals/year from 2025-2030, and ultimately ~14 individuals/year thereafter, the provincial government’s draft release plan projected that it is within the scope of biological and technical feasibility to restore a stable population of ≥250 mature individuals within 50 years (B.C. MFLNRORD 2021). The release plan is being adaptively managed following review of the results of the first two years (Government of B.C. 2023b).

Redundancy, connectivity, and stability:

Prior to impacts from human activity (that is, in its natural condition), the Spotted Owl had a relatively restricted distribution, concentrated in southwestern B.C. Although the precise bounds of its historical range (including extent of occurrence and area of occupancy) are unknown, it would have included three ecologically distinct sub-regions (the wet ‘Maritime’, moist ‘Sub‑maritime’, and dry ‘Continental’ sub-regions), with connectivity in habitat within these sub-regions and to the U.S.A, to support a stable and genetically diverse population. With connectivity in habitat, and stability in population and distribution characteristics, it is unlikely that any of the COSEWIC quantitative criteria associated with redundancy, fragmentation, and/or stability for assessment as Endangered would have been met for the species in its natural condition. For recovery to be considered feasible, it must be biologically and technically feasible to reverse the declines in population and distribution characteristics, and to ensure there is a connected network of habitat that will support at least 250 mature individuals. Through captive breeding and reintroduction (see above) and threat mitigation, it is considered to be within the scope of biological and technical feasibility to restore a stable population. Through habitat protection and threat mitigation, it is considered to be within the scope of biological and technical feasibility to ensure that there are no further habitat declines. Based on the configuration of regenerating and existing Spotted Owl habitat (see section 7 - Critical Habitat), it is considered to be within the scope of biological and technical feasibility to achieve a connected network of habitat sufficient to support ≥250 mature individuals within 50 years. Connectivity to the U.S.A. will always be reduced relative to historical conditions due to permanent habitat loss within developed portions of the Lower Mainland and Fraser Valley; however, some connectivity still exists and/or can be restored through long-term protection of maturing forest. In its recovered condition, the Spotted Owl would not meet the quantitative criteria for assessment as Endangered or Threatened based on A,B,C, or E COSEWIC indicators (see Table 2 in COSEWIC 2021).

Protection from human-caused threats:

There are ongoing human-caused threats that must be addressed (ceased, mitigated, or avoided) in order for the preceding key survival characteristics to be met and for recovery to be feasible. The most significant ongoing human-caused threats include: competition with a problematic native species (that is, the closely-related Barred Owl); habitat impacts caused by logging and wood harvesting, roads and railroads (including logging roads), and fire and fire suppression. It is biologically and technically feasible to cease or mitigate the human-caused threats of logging, road-building; and fire / increased fuel loads resulting from fire suppression. Barred Owls are now considered to be one of the highest-level threats to the Spotted Owl both in B.C. and range-wide in North America (section 4 of this document; USFWS 2011) and may currently pose a greater biological and technical challenge than habitat loss and availability. Barred Owl control programs (translocation and lethal removal) have been initiated within both the U.S.A. and B.C. (Diller et al. 2016, Gillis and Waterhouse 2020, Wiens et al. 2021) as an important component of Spotted Owl conservation efforts. Post-treatment monitoring studies in the U.S.A. have shown increases in local Spotted Owl site occupancy, survivorship and productivity within 4.5 years of (lethal) Barred Owl removal (Diller et al. 2016; Wiens et al. 2021). In more northern study areas there were longer lag times before reduced Barred Owl colonization rates and increased Spotted Owl responses were measured (Wiens et al. 2021). The longer lag times in northern sites have been attributed to two potential causes: 1) more established Barred Owl populations in these areas, and 2) lower numbers of Spotted Owls available to recolonize empty territories (Diller et al. 2016; Yackulic et al. 2019). Discernable Spotted Owl responses to Barred Owl removals have not yet been reported in Canada (Gillis and Waterhouse 2020); however, the planned re-introduction of Spotted Owls could help improve re-colonization rates. While there is uncertainty, it is still considered to be within the scope of biological and technical feasibility that impacts of Barred Owl can be managed successfully, to the extent that the preceding survival characteristics can be addressed.

2. Independence: Is the species currently able to persist in Canada independent of deliberate human interventions, and/or will it eventually be able to achieve and maintain independence in the state where condition (1) is met, such that it is not reliant on significant, direct, ongoing human intervention?

Yes. The Spotted Owl is currently nearing extirpation in Canada and requires significant, direct human interventions (that is, population augmentation through captive breeding; Barred Owl control) in the short-to-medium term (that is, within the next 20 years), in order for condition ‘1’ of recovery feasibility to be met. Barred Owl control is the primary intervention that may need to continue for a longer period (that is, beyond 20 years); however, habitat improvement/recovery is expected to improve Spotted Owl persistence in combination with Barred Owl control and may help reduce the necessary level of investment in Barred Owl removals in the future (Yackulic et al. 2019). Although there is a high level of uncertainty, it is considered to be within the scope of biological and technical feasibility that a point will be reached in the longer term (up to 50 years), where the Spotted Owl population has recovered such that it can remain stable in the absence of ongoing human interventions.

3. Improvement: Can the species’ condition be improved over when it was assessed as at risk?

Yes. It is biologically and technically feasible to meaningfully improve the condition of the Spotted Owl in Canada through addressing one or more key survival characteristics (as they pertain to results of human activity) such that the species’ risk of extinction or extirpation is reduced. Population stability and resilience may be improved, and population/habitat connectivity and redundancy restored, through a) ensuring a connected network of habitat, so that the habitat needed to support all life functions for a population of >250 mature individuals is available on the landscape when the recovering/recovered population needs it; b) continuing the captive breeding and reintroduction program, so that protected habitat is repopulated, and c) continuing Barred Owl control efforts, so that Spotted Owls can survive and reproduce successfully within protected habitats.

1. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) species assessment information

Date of assessment: April 2008

Common name (population): Spotted Owl caurina subspecies

Scientific name: Strix occidentalis caurina

COSEWIC status: Endangered

Reason for designation: This owl requires old-growth forests for its survival and has suffered a catastrophic population decline over the past 50 years as habitat is lost and fragmented. With the severely depressed population, an additional threat is the recent arrival of the closely related Barred Owl as a breeding bird in B.C.; this species competes with and hybridizes with the present species. Its historical population of about 500 adult owls in Canada has been reduced to 19, and only 10 of these are in breeding pairs. All adults are old and near the end of their breeding age and there is no recruitment of young owls into the population. If current trends are not reversed, extirpation will likely occur within the next decade.

Canadian occurrence: British Columbia

COSEWIC status history: Designated Endangered in April 1986. Status re–examined and confirmed in April 1999, May 2000, and April 2008.

* COSEWIC (Committee on the Status of Endangered Wildlife in Canada)

The above summary reflects population status information as of the 2008 COSEWIC assessment. Since 2008 there has been new information about historical and current population levels (summarized in section 3.2 – species population and distribution).

2. Species status information

The legal designation for the Spotted Owl on SARA Schedule 1 is Endangered (2003). Approximately 8% of the global (historical) range of the Spotted Owl is located in Canada (COSEWIC 2008). The species’ status ranks, globally and in the different parts of its range, are summarized in Table 1.

3. Species information

Spotted Owl, or Northern Spotted Owl, are English names given to the species. First Nations have other names for the species that reflect the diversity of Indigenous languages throughout its historic range.

Environment and Climate Change Canada recognizes that this recovery strategy does not currently reflect the deep cultural and spiritual significance of the species to some Indigenous peoples. We welcome future collaborations that respectfully explore other languages, and the connections between these owls, their relatives in human form, and the broader environment in the context of describing additional perspectives on the species, and to inform ongoing planning and implementation of recovery actions.

3.1 Species description

The Spotted Owl is a medium-sized owl averaging 45 cm in length and 90 cm in wingspan. Plumage is dark overall with brown feathers patterned by small pale spots over most of the body. The tail has narrow white horizontal bars and there are no “ear” tufts. Eyes are large, dark brown and are set within lighter brown facial disks (Forsman 1981; Gutiérrez et al. 1995). Age cohorts can be identified by differences in plumage characteristics. Juveniles <5 months old are identified by visible down feathers. Sub-adults (1-2 years old) and adults (>2 years) may be differentiated based on tail feathers; sub-adults have pointed tail feathers with white tips whereas adult tail feathers are rounded and usually mottled in colour (Forsman 1981). Males and females have similar plumage but females are ~15% larger (Blakesley et al. 1990; Gutiérrez et al. 1995).

3.2 Species population and distribution

3.2.1 Population

The global population of the Spotted Owl was estimated at roughly 6000 breeding pairs in the late 1980s (Thompson et al. 1990), with the bulk of the population (>90%) occurring in the U.S.A. (COSEWIC 2008). Local population declines were observed at demographic study areas within Washington, Oregon, and California between 1985 and 2013, with an overall mean annual rate of decline of 3.8% (Dugger et al. 2015). Although no formal global population estimates have been published in recent decades, an approximate current population estimate can be deduced using the annual rates of decline observed in long-term study areas; assuming a 6000-pair starting population and a 3.8-% mean annual decline from 1985-2021, the global population would now be <1500 pairs. An updated analysis of the long-term study area data including data from 1995 to 2017 (Franklin et al. 2021) suggests that declines may have become even sharper than the 3.8-% mean decline reported in Dugger et al. (2015), with some long-term study sites exhibiting mean annual declines as high as 9%. Declines have been most pronounced in Washington, Oregon and B.C., and less pronounced in California (Blackburn and Godwin 2003; Dugger et al. 2015; Franklin et al. 2021).

Before European settlement, the Canadian Spotted Owl population likely did not exceed 500 breeding pairs, or ~10% of the global population (Blackburn et al. 2002). In 1991, it was estimated at fewer than 100 potential breeding pairs (Dunbar et al.1991; Dunbar and Blackburn 1994) and by 2002 it had declined further to fewer than 33 (Blackburn and Godwin 2003). A survey of 10 previously-occupied sites in 2020 found one pair and one single owl at two sites (J. Gillis pers. comm. 2020). Continued occupancy of those two sites was reconfirmed in 2021 (J. Gillis pers. comm. 2021). As of mid-2022, only one female owl was thought to remain in the wild (Government of B.C. 2022). This suggests a decline of over 99% from estimated historical levels in Canada, with Canada now supporting <0.01% of the global (combined Canada and U.S.A.) population.

As outlined in the Recovery Feasibility Summary, a Spotted Owl captive breeding and reintroduction program has been in operation in B.C. since 2007. The first release occurred in August 2022, when three captive-bred male owls were released into two Wildlife Habitat Areas; one was later found injured and returned to captivity, and the other two died of unknown causes (Government of B.C. 2023a). In late June 2023, the previously injured captive owl and one additional male were released (Government of B.C. 2023b). As of September 2023, there were 37 known Spotted Owls in B.C.: one wild-born owl last confirmed in the wild during surveys in 2022, the two captive-bred owls released in 2023, and 34 owls in the captive breeding facility (27 adults and seven chicks born in 2023) (Government of B.C. representatives pers. comm. 2023)

The combined wild and captive population was relatively static between 2004 and 2020, where declines in the wild population in part resulted from individuals periodically being taken into the captive breeding program (Figure 1).

Figure 1. Known Spotted Owl population in Canada from 2004 to 2020 (Government of B.C. 2020). Note that annual inventory effort has varied for wild population counts.

3.2.2 Distribution

The Spotted Owl caurina subspecies is one of three subspecies of Spotted Owls found within North America (Figure 2). The caurina subspecies is distributed from the southwest mainland of B.C. through western Washington, western Oregon and the west coast of California, south to San Francisco Bay.

Figure 2. Approximate historical year-round range of Spotted Owls (three subspecies) in North America. (BirdLife International 2018). The caurina subspecies is often also referred to as the Northern Spotted Owl.

Historically, the Spotted Owl’s range in B.C. extended from the U.S.A. border north ~200 km to Carpenter Lake, and ~160 km from Howe Sound in the west to the Cascade Range in the east (Figure 3; Chutter et al. 2004). Within this range, there are three ecological sub-regions that differ in their mean annual precipitation and corresponding habitat characteristics: the wet ‘Maritime’, moist ‘Sub-maritime’, and dry ‘Continental’. Permanent range contraction occurred within the Lower Mainland and Lower Fraser Valley where once suitable habitat has been irreversibly lost to human development (Chutter et al. 2004; Figure 3); however, habitat remains within the rest of the historical range and could potentially be re-occupied by Spotted Owls. The remaining known wild individual was found within the Sub-maritime sub-region.

Figure 3. Approximate historical distribution of the Spotted Owl caurina subspecies in B.C.

3.3 Needs of the Spotted Owl

Historically, Spotted Owls occurred primarily within the Coastal Western Hemlock (CWH) and Interior Douglas Fir (IDF) biogeoclimatic zones in B.C. (SOMIT 1997; Sutherland et al. 2007). Their historical range would also have included parts of the Coastal Douglas Fir (CDF) zone, although that habitat has been permanently lost to human development (Chutter et al. 2004; Sutherland et al. 2007; Figure 3). The species is associated with mixed-coniferous forests characterized by: an uneven-aged cohort of trees; a multi-layered, relatively closed canopy; numerous large trees with broken tops, deformed limbs, and large cavities; and, numerous large snags and accumulations of logs and downed woody debris (Thomas et al. 1990; USDI 1992). These old-growth forests have the potential to buffer local warming, and thus function as local refugia for species reliant on cooler conditions (Spies et al. 2018; Dinerstein et al. 2019). In their 2016 climate change vulnerability assessment, Price and Daust recommended maintaining “sufficient old forest habitat to buffer changes in temperature and moisture and allow for dispersal” and “to maintain sufficient habitat as disturbance rate increases” as strategies to mitigate the effects of climate change for other old forest-associated species. They also recommended maintaining “landscape connectivity noting that natural landscapes provide the best opportunities for dispersal”.

Habitat configuration

Landscape-level configuration

In order for a stable Spotted Owl population to exist within a landscape, habitat must be configured such that it can support all critical life functions (breeding, roosting, foraging, and safe movement/dispersal) for the entire population. This requires patches of forested habitat capable of supporting the year-round needs of breeding pairs and resident individuals, as well an overall configuration of both the year-round habitat patches and seasonally-used dispersal habitat that maximizes survival/success of dispersing individuals. Juvenile Spotted Owls disperse from their natal site in the late summer / early fall of their first year, and then may disperse several more times and persist in the background as “floaters” for up to five years before settling and beginning to breed (Forsman et al. 2002). Breeding-age owls also occasionally disperse to new locations, particularly when their original location has been disturbed (Forsman et al. 2002; Jenkins et al. 2019; Jenkins et al. 2021).

Simulated landscape population modelling results for the species suggest that larger year-round habitat clusters are most likely to support stable long-term (100-year) occupancy by Spotted Owls due to the ability for individuals to disperse within their natal/original cluster versus having to leave their natal cluster and disperse across a less hospitable matrix (Lamberson et al. 1994; Marcot et al. 2013). Marcot et al. (2013) also found that clusters were more likely to exhibit stable long-term occupancy by Spotted Owls when they were spaced more closely together (<15 km). Being a highly-mobile species, Spotted Owls are capable of dispersing long distances. In an analysis of 1534 dispersal events in Oregon and Washington, Hollenbeck et al. (2018) reported a maximum dispersal distance of 177 km and a mean of 23.8 km (± 19.2 km standard deviation). Dispersal has also been observed across a range of habitat types. Large non-forested valleys, high-elevation subalpine forest, alpine tundra and large water bodies are the only features suspected to act as complete barriers to dispersal (Forsman et al. 2002; Chutter et al. 2004; I. Blackburn pers. comm. 2021). However, Spotted Owls must feed and escape predation to survive dispersal, and in moving through areas that lack foraging resources and security features, dispersing individuals are expected to incur an increased energetic/survival cost (Lamberson et al. 1994; Buchanan 2004; Sutherland et al. 2007; Marcot et al. 2013; Conlisk et al. 2020). In their simulated landscape population modelling, Marcot et al. (2013) found that as more of the landscape becomes suitable (that is, overall habitat more contiguous), all cluster size/spacing configuration options become sufficient to achieve low dispersal mortality and high long-term stability. There have been few empirical studies of dispersal habitat use and demographic associations; however, in a study in western Oregon, Miller (1997) showed that juveniles that used more clearcut areas during dispersal had higher mortality rates than those using more intact forest habitat. Similarly, in their analysis of 1534 successful juvenile dispersal events in the U.S.A., Hollenbeck et al. (2018) found that dispersal pathways tended to coincide with the distribution of forested areas along mountain ranges, as opposed to non-forested areas. Overall population stability is therefore most likely when a landscape includes not just large, closely configured habitat patches to support year‑round occupancy, but also habitat occurring in between year-round patches that provides foraging and security opportunities for dispersing birds.

Home range-level configuration

Within suitable landscapes, areas that adult/resident Spotted Owls occupy year-round are represented as home ranges. Home ranges can be occupied by unpaired resident birds, or by a breeding pair. A certain amount of habitat must be present in these areas to support nesting, roosting, and foraging life history functions (as described below). Further, this habitat must not be too fragmented, so that it can be accessed without excess energy expenditure and/or exposure to predation (Carey et al. 1992; Courtney et al. 2004; Sutherland et al. 2007). The mean area of habitat estimated to support a resident Spotted Owl home range varies between sub-regions: Maritime – 3010 ha, Sub-maritime – 2224 ha, Continental – 1907 ha (Chutter et al. 2004; Sutherland et al. 2007). In locations with contiguous mature or old-growth forested habitat, these numbers also represent minimum home range sizes. Home ranges become larger as habitat is more fragmented (Carey et al. 1992). The maximum energetically-viable home range sizes in fragmented landscapes could be more than three times larger than in contiguous habitats, and are estimated at 11,047, 7258, and 6305 ha in the Maritime, Sub-maritime, and Continental sub-regions, respectively (Sutherland et al. 2007). In continuous habitat, adjacent home ranges may overlap up to 25% (Sutherland et al. 2007).

During the breeding season, pairs concentrate their activities within a smaller area of their home range, in close vicinity to the nest grove. In Canada, most breeding season activities are estimated to occur within ~500 m of the nest tree (Blackburn et al. 2009).

Patch-level configuration

Due to a combination of both natural and anthropogenic disturbances, remnant Spotted Owl habitat in Canada exists in a range of patch^{Footnote 8} sizes, from large contiguous expanses to patches <1 ha in size. A patch’s size may impact whether it can provide functional habitat for a Spotted Owl. Ten hectares has been estimated by experts within Canada as the minimum habitat patch size within which preferred prey can persist and thus Spotted Owls can successfully forage (reviewed in Sutherland et al. 2007). In addition to absolute size, the irregularity of a patch may also impact its utility for Spotted Owls. Research from Pacific Northwest forests has shown that microclimate (including humidity and solar exposure) can be impacted up to ~100 m from an edge (Kremsater and Bunnell 1999). These impacts may be particularly pronounced for species of fungi and lichens, which are often adapted to the cooler, moister, darker conditions associated with interior forest (Crockatt 2012; Gauslaa et al. 2018). Spotted Owls in Canada feed disproportionately (>40% of diet) on Northern Flying Squirrels (Glaucomys sabrinus; Horoupian et al. 2004), which in turn feed preferentially on fungi and lichens associated with coniferous forested habitats (Carey 1991; Carey et al. 1992; Waters and Zabel 1995). In small or highly irregular forest habitat patches with high edge-to-interior ratios, the conditions necessary to sustain foraging resources for Northern Flying Squirrels may not exist. Competitors (of Spotted Owls) that are better adapted to foraging within diverse habitats may also over-exploit preferred prey species in openings and along edges, further reducing prey availability for Spotted Owls in small or irregular habitat patches (Wilson and Forsman 2013; Wiens et al. 2014).

Habitat attributes

Nesting

Spotted Owls do not build their own nests but depend on naturally occurring or previously constructed (by other raptor species) nest sites (Chutter et al. 2004, Waterhouse et al. 2012; Wilk et al. 2018). Nest sites include broken treetops, tree cavities, abandoned raptor nests, mistletoe brooms, and debris accumulations captured in branches (Forsman et al. 1984, Dawson et al. 1986, Waterhouse et al. 2012; Wilk et al. 2018). In captivity, nesting has occurred in artificial cavities (McCulligh 2019, see also Gutierrez et al. 1995). In general, cavities are more often used in moist climates and platforms are more frequently used in drier climates, particularly where cavities in trees >50 cm in diameter are not available (Chutter et al. 2004). In a survey of 14 known nest trees in B.C., Waterhouse et al. (2012) found that nest cavities were in trees averaging 88 cm in diameter (± 26.8 cm standard deviation). A variety of different tree species are used for nesting within the species’ range although large Douglas-fir may be selected more frequently in the drier regions (Waterhouse et al. 2012; Wilk et al. 2018). In the wetter regions, Western Hemlock and Western Redcedar have been used in equal proportion to Douglas-fir (Forsman and Giese 1997; Wilk et al. 2018). Nest site fidelity^{Footnote 9} is high and re-use of nest structures is common (Forsman et al. 1984).

Breeding Spotted Owls may experience stress, lower reproductive output, and disrupted nesting behaviours when exposed to acute noise within their nesting areas (Wasser et al. 1997, Hayward et al. 2011, USFWS 2020), therefore, in order to successfully carry out breeding functions they also require nesting areas to be free of significant acoustic disturbance during the breeding season. Acoustic disturbance significant enough to impact nesting functions can result from activities that result in an overall sound level above 90 db (for example, operation of large machinery, use of chainsaws, blasting, operation of large engines and engine brakes, operation of motorized recreational vehicles) or that increase the sound level above ambient conditions by over 20 db (USFWS 2020).

Roosting and escape

Spotted Owls require roosting sites that provide good protective cover from both inclement weather and predators. The multi-storied nature and high percentage canopy closure of old-growth forests enables thermoregulation and escape from inclement weather, as well as providing protection from predators (Blackburn et al. 2009). The Spotted Owl is easily subjected to heat stress and reduces its exposure by moving between roosting habitats in different parts of the canopy (Barrows 1981). The closed canopies of old-growth habitats also provide refuge from rain and snow (North et al. 2000). Great Horned Owls (Bubo virginianus) are the primary predator of the Spotted Owl (Gutierrez et al. 1995), and favour edge habitats and openings where they have greater access to prey (Artuso et al. 2013). Susceptibility to Great Horned Owl predation may thus be minimized in areas with intact, contiguous old-growth/mature forest (Johnson 1993).

Foraging

Spotted Owls require habitat with characteristics that promote abundant and accessible prey, which is primarily comprised of arboreal and semi-arboreal small mammals (Chutter et al. 2004; Wiens et al. 2014). Studies in western Washington and B.C. showed that Northern Flying Squirrels, Bushy-tailed Woodrats (Neotoma cinerea), and Deer Mice (Peromyscus sp.) were the most common prey for Spotted Owls in the northern extent of the Spotted Owl’s range (Forsman et al. 2001; Horoupian et al. 2004; Wiens et al. 2014). The abundant large coarse woody debris (CWD), standing snags, and diverse shrub layers present within old-growth forests support prey populations by providing moist microclimates, protective cover for movement, nest/burrow sites, and food in the form of fungi, plants and invertebrates (Carey 1991; Carey et al. 1997; Carey et al. 1999; Wilson and Forsman 2013). The open mid-storey structure of old-growth habitats also enables Spotted Owls to have more efficient access to those prey through providing longer sightlines and unimpeded flight paths (Chutter et al. 2004; D’Anjou et al. 2015).

Safe movement / dispersal

Like resident Spotted Owls, dispersing individuals require available prey and security features, therefore, old-growth and mature forests (that is, the same forests that support nesting/roosting and foraging) are understood to provide ideal conditions (reviewed in Buchanan 2004). Where no habitat capable of supporting foraging and security exists between two natal patches, dispersal success between those patches is likely to be reduced, ultimately reducing long-term patch occupancy and population stability. Safe movement/dispersal is best-supported by nesting/foraging quality habitat located either within year-round forested habitat patches (enabling within-patch dispersal) or in between those patches. Spotted Owls may traverse forested habitat in other seral stages during dispersal; however, it is not yet clear what other habitat attributes/configurations may contribute to dispersal success (Buchanan 2004). Research will be required to evaluate drivers of dispersal success in Canada and determine whether additional habitats should be identified as important for supporting safe movement.

Distribution of competitors

In addition to habitat amount, quality and configuration, the distribution and abundance of the Spotted Owl’s primary competitor, the Barred Owl, has been shown to strongly influence Spotted Owl occupancy across the landscape (Dugger et al. 2011; Dugger et al. 2015; Yackulic et al. 2019; Jenkins et al. 2019). Barred Owls reduce Spotted Owl occupancy of otherwise suitable habitat through both competition for prey (exploitative competition) and territorial displacement (Dugger et al. 2011; Wiens et al. 2014; Jenkins et al. 2021). See Section 4 (Threats) for more details.

Classification of habitat for the Spotted Owl

The Vegetation Resource Inventory^{Footnote 10} (VRI) geospatial database provides detailed information about the characteristics of forests in B.C. The VRI attributes used to classify forests as potentially suitable for the Spotted Owl in B.C. (not accounting for configuration considerations) are summarized in Table 2. ‘Nesting’ quality habitat is characterized by old, tall, low elevation stands, and ‘foraging’ quality habitat is characterized by mature, moderately tall stands that may extend further upslope. Both ‘nesting’ and ‘foraging’ quality habitats are considered to have characteristics that also support roosting and safe movement / dispersal. Nesting quality habitat is used disproportionately relative to its availability on the landscape, whereas foraging quality habitat is used in proportion with its availability on the landscape (Forsman et al. 1984; Carey et al. 1990; Carey et al. 1992).

The provincial government is also continuing to develop and refine habitat classification approaches as part of its Stewardship Baseline Objectives Tool (Government of B.C. 2021).

4. Threats

The Spotted Owl threat assessment is based on the IUCN-CMP (World Conservation Union–Conservation Measures Partnership) unified threats classification system. Threats are defined as the proximate activities or processes that have caused, are causing, or may cause in the future the destruction, degradation, and/or impairment of the entity being assessed (population, species, community, or ecosystem) in the area of interest (global, national, or subnational). Limiting factors are not considered during this assessment process. For purposes of threat assessment, only present and future threats are considered. Historical threats, indirect or cumulative effects of the threats, or any other relevant information that would help understand the nature of the threats are presented in the Description of Threats section.

4.1 Description of threats

Based on IUCN threat evaluation criteria, the overall range-wide threat impact for the Spotted Owl in Canada is assessed as ‘very high’. There is one threat that is assessed as ‘very high’ impact, one that is assessed as ‘high’ impact, two threats that are assessed as ‘medium’ impact, seven threats that are assessed as ‘low’ impact, and numerous threats that were evaluated as having ‘negligible’ or ‘unknown’ impacts, within the 10-year IUCN assessment timeframe (Table 3). Although threats related to habitat loss from sources other than logging and wood harvesting (for example energy production and mining, transportation and service corridors, recreational activities) are assessed as less than ‘high’ impact, all sources of habitat loss have cumulatively greater impacts than when assessed individually.

The captive breeding facility near Langley, B.C., represents an ex-situ location (that is not part of the wild population), and as such, threats to this location are considered separately, and not included in the development of the threat calculation table. Potential threats to the ex-situ location include:

• noise disturbance (for example from construction, and railway, aircraft, and vehicle traffic) during the breeding season, which can increase individual stress levels and reduce reproductive output when it occurs near nesting areas (Wasser et al. 1997, Hayward et al. 2011) as well as potentially altering nesting behaviours (USFWS 2020); and
• disease and other health concerns, and natural disasters, the potential impacts of which are elevated due to all captive owls being in a single geographic location. These threats are mitigated at the breeding facility through biosecurity protocols, staff training and experience, and separation of individual owls around the property (McCulligh 2023)

Very high impact threats

IUCN 8.2 – Problematic native species

The Barred Owl is native to eastern Canada but has expanded its range westward and southward. This is hypothesized as being a consequence of human activities that either directly or indirectly resulted in the introduction of trees across the previously tree-less prairie regions of central North America, for example, through European settlers excluding fires historically set by First Nations, suppressing wildfires, extirpating American Bison (Bison bison), and planting trees. In the 1960s Barred Owls began to overlap the range of the Spotted Owl in B.C. (Campbell et al. 1990; Dunbar et al. 1991). Barred Owls were detected at all 10 of the previously-occupied Spotted Owl survey sites visited in 2019 (J. Gillis pers. comm. 2019). They have also been detected extensively along general owl survey routes throughout the Spotted Owl’s historical range. Barred Owls thrive in a variety of forest types and seral stages and have adapted to more varied food sources than have Spotted Owls (Livezey et al. 2009a&b; Wiens et al. 2014; Diller et al. 2016; Dugger et al. 2015). Barred Owls threaten the Spotted Owl primarily through competition for habitat and prey (Dugger et al. 2011). This resource competition and competitive displacement has been found to reduce Spotted Owl fecundity and recruitment, leading to overall population declines (Jenkins et al. 2021). Hybridization and predation have also been observed on rare occasions (Leskiw and Gutiérrez 1998; Kelly and Forsman 2004); however, these are not considered serious threats (USFWS 2011).

In recognition of the severity of this threat, Barred Owl control programs have been initiated within the range of both the American and Canadian Spotted Owl populations (Diller et al. 2016; Dugger et al. 2015; Gillis and Waterhouse 2020; Wiens et al. 2021). American programs have employed lethal removal and the B.C. program has employed a combination of translocation and lethal removal. Results from Barred Owl removal studies have varied with more immediate success at the southern edge of the range and slower results at the northern edge of the range. In California, the annual Spotted Owl population growth rate four years after (lethal) removals was 1.029 (increasing) on removal sites versus 0.870 (declining) on control sites (Diller et al. 2016), and in Oregon and Washington, increases in Spotted Owl occupancy and fecundity and decreases in local extinction rates were observed 4.5 years following Barred Owl removals (Wiens et al. 2021). However, a longer lag time was observed in the more northern sites in Oregon and in Washington (Wiens et al. 2021) and in B.C. (lethal and non-lethal) removal efforts have not yet been sufficient to offset Barred Owl recolonization rates (Gillis 2016a&b; Gillis and Waterhouse 2020).

Diller et al. (2016) suggested that Spotted Owl populations further north may experience slower recovery following Barred Owl removal because Barred Owl populations are more well‑established (so require more intensive and sustained removal efforts to overcome recolonization by floaters/dispersers) and Spotted Owl populations are too small to recover quickly (fewer floaters/dispersers waiting to take up available territories). The supplementation of the B.C. Spotted Owl population through re-introduction may counter this effect. Supplemental feeding of released individuals may also bolster post-release survival. Habitat improvement/recovery is also expected to improve Spotted Owl persistence in combination with Barred Owl control and may help reduce the necessary level of investment in Barred Owl removals in the future (Yackulic et al. 2019). However, it is unknown whether this threat can be mitigated or avoided to the extent that the Spotted Owl can recover without ongoing human intervention (Bodine and Capaldi 2017). Research and adaptive management will be required to determine if and how threats from Barred Owl can be effectively addressed over the long term and thus whether a recovered Spotted Owl population can be sustained in the absence of ongoing Barred Owl control.

High impact threats

IUCN 5.3 – Logging and wood harvesting

Logging has had and continues to have severe impacts on the Spotted Owl, including direct loss of old forest habitat (loss of nesting, roosting, and foraging habitat attributes) and fragmentation (COSEWIC 2008, Chutter et al. 2004). The primary impact of forestry-related habitat fragmentation appears to relate to foraging energetics (reviewed in Courtney et al. 2004). As foraging patches become more dispersed following forest harvest, they may no longer be accessible within an individual’s energetic budget, and so the individual may starve or be forced to disperse to a new location (Sovern et al. 2014; Jenkins et al. 2019). Further, as residual patches become smaller and more irregular, they may no longer be able to support adequate numbers of the Spotted Owls’ preferred prey species (see section 3.3 – Needs of the Spotted Owl). Additional impacts of logging can include noise disturbance associated with logging operations, when operations take place within 400 m of nesting areas (Wasser et al. 1997, Hayward et al. 2011, USFWS 2020). Fragmentation and the conversion of the landscape from old-growth coniferous forest to other habitat types may also increase the exposure of Spotted Owls to their primary predator, the Great Horned Owl (Johnson 1993). Competitive pressure may also be greater within harvested landscapes as Barred Owls are better able to adapt to the more varied seral stages and food sources present in harvested landscapes than are Spotted Owls (Hamer et al. 2007; Wiens et al. 2014; Yackulic et al. 2019).

Improved forestry practices on Crown Land under the provincial Forest and Range Practices Act as well as Spotted Owl-specific habitat protection initiatives under the Spotted Owl Management Plans (1 and 2) have partially reduced forestry impacts on Spotted Owl by requiring or promoting the retention of veteran trees, snags, and riparian areas; reducing cut block size; increasing retention area size; and providing some measure of habitat protection for tracts of old forest through the designation of Wildlife Habitat Areas (WHAs), Old Growth Management Areas (OGMAs) and Ungulate Winter Ranges (UWRs) (Government of B.C. 2009). However, a large amount of nesting and foraging class habitat within the Spotted Owl’s range still falls within the unprotected portions of the Timber Harvesting Land Base (THLB), and harvesting continues to both remove and isolate habitat.

Medium impact threats

IUCN 4.1 – Roads and railroads

Spotted Owl nesting habitat is located within low-land forests where there has been increasing concentration of roads for logging and other purposes. Major railway corridors also fall in these areas. Road-building and expansion results in direct and often permanent habitat loss through eliminating old forest habitat within the immediate road surface and managed right-of-way. Roads and railways also expose individuals to risk of collisions (Forsman et al. 2002), and noise disturbance from road and rail traffic can increase individual stress levels and reduce reproductive output when it occurs near nesting areas (Wasser et al. 1997, Hayward et al. 2011) as well as potentially altering nesting behaviours (USFWS 2020). Great Horned Owls may also be more prevalent along linear corridors such as roads and railways, putting Spotted Owls at greater risk of predation when these features transect their habitat (Johnson 1993). Road‑building will continue to accompany resource extraction/development activities (for example, forest harvesting). New rail lines are not being planned within the Spotted Owl range.

IUCN 7.1 – Fire and fire suppression

Within the drier Sub-maritime and Continental sub-regions, vigorous fire protection by the B.C. Forest Service between the 1960s and 1990s extended fire return intervals well beyond their historical range, creating an accumulation of woody fuels, which can lead to more intense, stand-replacing wildfires (Wong et al. 2003, ESTR Secretariat 2014). Within the American portion of the range, Davis et al. (2016) estimated that 191,900 ha of nesting and roosting habitat on federal lands had been lost to wildfires between 1994 and 2013, four times the amount of habitat that was harvested. A similar analysis in the Canadian portion of the species’ range by the Canadian Wildlife Service using annual fire disturbance mapping from 1985 to 2015 (Hermosilla et al. 2015a&b, 2017), indicated that 47,915 ha of forests within the areas classed as suitable for the Spotted Owl has been detectably^{Footnote 11} impacted by fire across that 30‑year period, primarily within the drier Sub-maritime and Continental sub-regions, with annual burn areas as large as 4156 ha. Fire impacts are expected to increase in the Spotted Owl range under climate change (reviewed in Spies et al. 2018). Within the wetter regions (that is, Maritime sub-region in Canada), overall area impacted by fire is expected to remain relatively low due to the naturally very low fire incidence there, even when multiplied according to climate projections (Littell et al. 2010). However, in the drier sub-regions, where existing fire intervals are shorter and fire extents larger, the increase will translate into more significant habitat impacts (reviewed in Spies et al. 2018). Applying an assumption that future annual burn rates under climate change are likely to approximate the upper end of the annual burn rates observed in the previous 30 years (that is, up to 4156 ha per year), it is estimated that as much as 207,800 ha of Spotted Owl habitat within Canada will be impacted by fire within the 50-year recovery timeframe. This projection was supported during the 2021 fire season when as much as 7700 ha of Spotted Owl habitat may have been impacted by fire (based on B.C. Fire Perimeters mapping). Although not all of these fires will be stand-destroying and result in long-term habitat loss, projections of increasing incidence and area of catastrophic fire under climate change do indicate that fire will be a significant driver of habitat loss in the future (reviewed in Spies et al. 2018; Price and Daust 2016). Wildfire risk reduction efforts could counter this risk; however, such efforts also have the potential to impact Spotted Owl habitat directly (through loss of potential nesting trees and the features required to support prey populations) when crews target downed wood (CWD) and snags for removal. Addressing the risk of fire and climate change‑mediated increases in fire impacts to the Spotted Owl will require a number of strategies, including increasing the overall area conserved in support of Spotted Owl recovery to account for projected fire impacts, including adequate representation within and connectivity to the wetter western portion of the range (where disturbance rates are expected to re lower), ensuring a high level of connectivity as well as alternate connections to provide refugia and enable recolonization/recovery following disturbance, and employing carefully-managed wildfire risk reductions efforts (for example, avoiding irreplaceable old forest elements such as snags and CWD) in more fire-prone regions that have surplus fuel loads as a consequence of historical fire suppression.

Low impact threats

IUCN 1.1 – Housing and urban areas and IUCN 1.2 – Commercial and industrial areas

Historically (prior to the 1930s), urbanization (and associated commercial and industrial development) resulted in broad-scale loss of mixed-coniferous forests throughout the Lower Mainland (Boyle et al. 1990) as well as portions of the Lower Fraser Valley where agricultural development did not predate urbanization. However, most old forest habitat within range of these population centers has now been converted to urban areas (Chutter et al. 2004; Sutherland et al. 2007), so this is not expected to represent a significant, broad-scale threat in the next decade.

IUCN 1.3 – Tourism and recreation areas

Several large ski resorts exist within the Maritime sub-region in areas with habitat for the Spotted Owl. Expansion of resort infrastructure within existing ski areas could lead to additional, localized, habitat loss. Planning is also underway for one new ski resort in the Sub-maritime sub-region, although proposed development is largely within the footprint of an existing mine, so additional habitat impacts may be minimal. Use of provincial parks and other accessible Crown lands within all three sub-regions has also increased dramatically in the last decade (B.C. Parks 2018; J. Hirner, pers. comm. 2020), creating pressure to expand trails and park infrastructure into potential Spotted Owl habitat. However, this threat applies to a relatively small percentage of the species’ range, so the overall impact is assessed as low.

IUCN 3.2 – Mining and quarrying

Mining and mineral exploration activities are uncommon in the Spotted Owl range; however, because they are exempt from the prohibitions on forest harvest under the General Wildlife Measures in WHAs (Government of B.C. 2019), such activities have the potential to cause habitat loss even in areas under timber harvest constraints. Any Spotted Owls nesting or foraging within the vicinity of mining or quarrying operations could also be disturbed by operational noise, with similar impacts as from noise associated with wood harvesting and road construction or traffic. However, this threat applies to a relatively small percentage of the species’ range, so the overall impact is assessed as low.

IUCN 4.2 – Utility and service lines

As with roads, habitat clearing associated with utility and service line construction (which includes pipelines) will result in some direct habitat loss and the linear edge habitats created could impact prey populations and increase predator exposure. Any Spotted Owls nesting or foraging within the vicinity of utility or service lines during construction or maintenance could also be disturbed by machine noise, with similar impacts as from noise associated with wood harvesting and road construction or traffic. However, this threat applies to a relatively small percentage of the species’ range (one major utility line project was being planned when the threats calculator was prepared, the construction of which was completed in 2023), so the overall impact is assessed as low.

IUCN 6.1 – Recreational activities

Backcountry recreation use has increased dramatically within Southern B.C. Visitor numbers at B.C. Parks in southern regions increased by 60% between 2007 and 2017 (B.C. Parks 2018). Recreational use of other accessible Crown lands has also increased dramatically in the last decade (J. Hirner, pers. comm. 2020). As more backcountry users visit parks and recreation areas where Spotted Owls nest, the potential for human disturbance increases. Motorized recreation, in particular, could disturb Spotted Owls nesting in the vicinity of recreational trails/areas. However, this threat applies to a relatively small percentage of the species’ range, so the overall impact is assessed as low.

Negligible and unknown impact threats

Eleven individual threats or complete IUCN threat categories were classified as having a negligible impact on the Spotted Owl based on limited spatial overlap with the species’ range and habitat and/or no anticipated impacts within the 10-year IUCN-CMP assessment timeframe.

A further five threats were classified as having unknown impacts within the 10-year assessment timeframe, most related to climate change. Climate change impacts could be significant, particularly within the 50-year recovery timeframe, but there remains considerable uncertainty around the direction and magnitude of climate change-mediated shifts in weather, natural disturbance, and forest health within the Spotted Owl range, as well as the likely response of Spotted Owls to those changes (reviewed in Courtney et al. 2004; Spies et al. 2018).

A comprehensive review of climate modelling research has been undertaken for the Northwest Forest Plan (in the U.S.A.), which is focused on management of old-growth forests for Spotted Owl recovery (Spies et al. 2018). Most models assessed within that review predicted warmer, drier summers and potentially warmer and wetter winters. Conditions are projected to exceed the 20th-century range of variability by the 2050s. These predictions are supported by modelling that also covers the Canadian portion of the Spotted Owl’s range (Wang et al. 2016). A comprehensive analysis of Spotted Owl survival and recruitment in relation to predictors including climate (Dugger et al. 2015) found an association between climate variables and both juvenile recruitment and adult annual survival. Recruitment was lowest when conditions during the previous winter were cold and wet, and highest when the previous winter was cold and dry. Observed survival rates were higher when winters were relatively warmer and drier. Summer temperature extremes could also impact recruitment rates; the heat dome of 2021 had significant impacts on juveniles in the fledge stage (J. Gillis, pers. comm. 2021). However, given that predicted temperature and precipitation patterns under climate change could lead to both positive and negative changes to different demographic rates, it is difficult to generate an overall prediction of how Spotted Owl populations may be impacted.

When it comes to habitat impacts from climate change, lower elevation, moist vegetation zones (for example, those within much of the Maritime sub-region in Canada) are expected to experience decreased growth and productivity, especially where tree species are already water limited during the growing season (reviewed in Spies et al. 2018). Within drier forests (for example, those within the Continental sub-region and some portions of the Sub-maritime) most models predict an increased role of fire, including more area burned and larger patches of high-severity fire (reviewed in Spies et al. 2018; Price and Daust 2016), which will increase the rate of fire-related habitat loss, relative to past decades (for example, see IUCN-CMP 7.1, above). A preliminary assessment of anticipated climate change vulnerability for a number of species in B.C. was conducted in 2016 (Price and Daust 2016). Although the Spotted Owl was not amongst the species assessed, other old forest-associated species with similar ranges were assessed as having moderate-high climate change vulnerability, primarily due to increased climate change‑mediated natural disturbance within their old forest habitats.

5. Population and distribution objectives

Population and distribution objective

To recover the Spotted Owl in Canada by restoring a stable population of at least 250 mature individuals distributed within a connected network of habitat representative of all three sub‑regions within the species’ historical Canadian range, and linked to the larger population in the U.S.A.

Rationale

Historically, the Spotted Owl’s restricted range and small population size would have made it naturally precarious (that is, naturally falling within COSEWIC’s Threatened status); however, the population was believed to be large enough to be stable, with connectivity/representation across its range. In contrast, the species is now assessed as Endangered on the basis of compromised stability, redundancy, connectivity, and resilience.

There has been permanent loss of habitat within the Lower Mainland and Lower Fraser Valley (now a major human population center), which both reduces the overall area available to the species in Canada and restricts the potential for continued gene flow between Canada and the U.S.A. (Chutter et al. 2004). However, portions of habitat within the remainder of the range, across all three historically-occupied sub-regions are either still intact or are close to re‑acquiring the attributes of Spotted Owl habitat, such that if they are maintained now they will contribute to habitat patch size, quality and connectivity, and help to restore historical representation. Other limitations to recovery are also believed to be manageable over the long term, given current/anticipated tools (Chutter et al. 2004; Government of B.C. 2020; B.C. MFLNRORD 2021). Assuming that planned actions are undertaken to i) protect and restore sufficient Spotted Owl habitat; ii) control Barred Owls to reduce interspecific competition; iii) breed Spotted Owls in captivity, and iv) release captive-born Spotted Owls to supplement wild populations and achieve successful breeding of reintroduced owls in the wild, the provincial government projects that it is within the scope of biological and technical feasibility to achieve the COSEWIC threshold for Threatened status (that is, ≥250 mature individuals) within 50 years (B.C. MFLNRORD 2021). The amount, configuration and attributes of habitat that is necessary to achieve this population target in context of distribution objectives (connectivity and representation) are described in section 7 of this document. Recovery of Spotted Owls will require significant targeted interventions in the form of population augmentation and competitor control in the short- to medium-term (10-30 years), therefore, short-term recovery statements toward meeting the objective are set out below, to facilitate recovery implementation.

Short-term recovery statements toward meeting the population and distribution objective

1. Immediately cease human-caused destruction of biophysical attributes of old-growth forests as outlined in section 7.2 of this document and mitigate all other human-caused threats as outlined in section 4.1 that would cause loss of habitat needed for recovery (that is, the critical habitat)
2. Re-introduce at least 50^{Footnote 12} captive-bred Spotted Owls to the wild by 2033, with at least 10 released individuals surviving to become resident adults
3. Complete annual Barred Owl surveillance at sites occupied by Spotted Owls and/or where reintroductions are planned, and remove all Barred Owls that are detected

6. Broad strategies and general approaches to meet objectives

6.1 Actions already completed or currently underway

Habitat protection, enhancement and stewardship

Management planning

In 1997, a Spotted Owl Management Plan (SOMP) was developed with a goal of stabilizing (and optimistically improving) the population over the long-term, without exceeding a 4% reduction in the Timber Harvesting Land Base (THLB) (that is, SOMIT 1997). SOMP established 21 Special Resource Management Zones (SRMZs) that included pre-existing protected areas as well as Crown forest land. Within the SRMZs that fell outside protected areas, 67% of the habitat was to remain suitable for the Spotted Owl, while the remaining 33% was eligible for harvest using specific prescriptions.

In 2009, an updated version of SOMP (‘SOMP2’) was released, which involved transferring most SRMZs into Long Term Owl Habitat Areas (LTOHAs; managed for Spotted Owl conservation) and Managed Future Habitat Areas (MFHAs; managed for forest harvest with consideration for long-term Spotted Owl habitat development), adjusting some managed area boundaries, and creating updated harvesting guidelines/designations (Blackburn et al. 2009; Government of B.C. 2009). The requirement to limit impacts on the THLB to <4% remained, so there was no increase in the area managed for Spotted Owl recovery under the new plan. In 2012, the LTOHA and MFHA areas under SOMP2 became legally-designated Wildlife Habitat Areas (WHA) with General Wildlife Measures (GWM). Thirty-two WHAs are now in place to provide a measure of protection to areas large enough to support one or more breeding pairs of Spotted Owls (Government of B.C. 2023). Within the LTOHA WHAs forest harvest is largely prohibited, and within the MFHA WHAs harvest is permitted subject to conditions.

Additional regulatory measures

In addition to provincial WHAs, other protected area designations^{Footnote 13} provide some measure of protection for Spotted Owl habitat. These include: Provincial/Municipal/Regional Parks; Provincial Protected Areas, Recreation Areas, Ecological Reserves and Conservancy Areas; Sea-to-Sky Wildland Areas; Metro Vancouver Watersheds; Ungulate Winter Ranges, Old Growth Management Areas, and Wildlife Habitat Areas for other species; and National Wildlife Areas.

Active population management

Captive breeding and release

In 2007, the Spotted Owl Population Enhancement Team, an arm’s-length independent panel that was established by the provincial government, determined that the wild population was so small and isolated that extirpation was a certainty. It therefore made the recommendation to capture either all or a subset of the remaining wild individuals and establish a captive-bred population whose offspring could be re-introduced into the wild (Fenger et al. 2007). The provincial government elected to capture only a subset of the remaining wild individuals to establish the captive breeding program and allow a small wild population to persist. The home ranges that owls were removed from to establish the captive breeding program were all designated as LTOHAs at that time. They were then converted into WHAs in 2012.

The Spotted Owl captive breeding program has been in operation in B.C. since 2007 (Government of B.C. 2021). It had slow initial success rates, but a now younger breeding population and improvements in husbandry techniques have resulted in higher breeding output in recent years (McCulligh 2023, Northern Spotted Owl Breeding Program n.d.). However, given the small size of the captive breeding population, even modest increases in adult mortality or declines in the average egg fertility rate could have significant consequences for the recovery program.

As of spring 2023, the breeding program had produced 31 captive born owls (Government of B.C. representatives, pers.comm. 2023). The first trial release occurred in August 2022, when three captive-bred male owls were released into two Wildlife Habitat Areas; one was later found injured and returned to captivity, and the other two died of unknown causes (Government of B.C. 2023a). Additional details about the 2022 release considerations and protocols are included in McCulligh 2023. In late June 2023, the previously released captive owl and one additional male were released following updated protocols (Government of B.C. 2023b). Following those releases, as of September 2023, there were 34 Spotted Owls at the breeding facility (Government of B.C. representatives, pers.comm. 2023).

Barred Owl control

In 2007, the provincial government initiated a Barred Owl removal program, with target sites including active Spotted Owl territories and sites planned for re-establishment through the release of captive-bred owls (Fenger et al. 2007). Between 2007 and fall 2022, a total of 207 Barred Owls were removed from active (that is, currently occupied) Spotted Owl territories and from proposed Spotted Owl re-establishment sites (Gillis and Waterhouse 2020; Government of B.C. representatives, pers.comm. 2023). Removals were a combination of capture and translocation (at re‑establishment sites) and lethal removal via shooting (at active sites). Between 2007-2021, 108 Barred Owls were captured and translocated away from proposed re-establishment sites and 80 were removed from active Spotted Owl sites using lethal methods. The combined removal effort reduced the number of detected Barred Owls overall, but as of 2016 had not been sufficient to overcome local re-colonization rates. Moving forward, adaptations to removal methods could improve the effectiveness of Barred Owl removal efforts in B.C. (Gillis and Waterhouse 2020). The augmentation of the wild population through the release of captive-bred owls may also increase the rate of Spotted Owl recolonization of removal sites. Habitat improvement/recovery is also expected to improve Spotted Owl persistence in combination with Barred Owl control, reducing the necessary level of investment in Barred Owl removals in the future (Yackulic et al. 2019).

Inventory, monitoring, and population evaluation

Owl population inventory and monitoring

From the 1990s to 2008, inventories were conducted to determine the range, distribution, and abundance of the Spotted Owl in B.C., as well as to assist in resource management decisions (Blackburn et al 2002; Hobbs 2004&2005; J. Gillis pers. comm. 2019). An organized banding program (attaching unique leg bands) was initiated in 1998 to identify individuals and monitor their movements and habitat occupancy. Between 1998 and 1999, transmitters were affixed to several breeding pairs to monitor habitat use and home range sizes (Chutter et al. 2004). Between 2003 and 2014, juvenile owls were affixed with transmitters to ascertain their dispersal movements and overwinter survival (Hobbs 2004&2005; J. Gillis pers. comm. 2019). Beginning in 2015, inventory/monitoring efforts became focused on revisiting previously known Spotted Owl sites to assess re-occupancy, as well as inventory of sites identified for potential re-introduction through release of captive-bred owls (Gillis 2016a&b; 2017; 2018). Starting in 2016, a pilot program was launched to assess the utility of Autonomous Recording Units (ARUs) in Spotted Owl and Barred Owl monitoring (Gillis 2016a&b; 2017; 2018). ARUs continue to be used for monitoring purposes (McCulligh 2023), although Spotted Owls are known to suppress their vocalizations in the presence of Barred Owls (Dugger et al. 2011; Wiens et al. 2014). As such, the absence of Spotted Owl detections from ARU data is not conclusive evidence of absence of Spotted Owls. ARU data informs the implementation and effectiveness monitoring of the Barred Owl control program (McCulligh 2023).

Habitat and population evaluation

In 2007, the Canadian Spotted Owl Recovery Team (CSORT), with the support of Cortex Consultants and Andrew Fall Gowlland Technologies Ltd, developed an integrated modelling framework designed to inform the Spotted Owl recovery program in B.C. and associated habitat management (Sutherland et al. 2007). The framework included models for spatial landscape projection, ecological classification, cross-scale habitat assessment, population dynamics, and reserve selection. This work informed changes / refinements in habitat protection under SOMP 2 (Government of B.C. 2009 and 2020) as well as the approach for the identification of critical habitat in this document.

6.2 Strategic direction for recovery

7. Critical habitat

Section 41 (1)(c) of SARA requires that recovery strategies include an identification of the species' critical habitat, to the extent possible, as well as examples of activities that are likely to result in its destruction. This federal recovery strategy identifies critical habitat to the extent possible, based on the best available information for the Spotted Owl.

It is recognized that the ‘acoustic’ critical habitat identified below is insufficient to achieve the population and distribution objectives for the species. A schedule of studies (Section 7.2) has been developed to provide the information necessary to complete the identification of acoustic critical habitat (defined below) that will be sufficient to meet population and distribution objectives. For core critical habitat (defined below), boundaries may be revised, or additional core critical habitat may be added in the future, if additional information supports such changes. The identification of critical habitat will be updated when the information becomes available, in a revised recovery strategy.

7.1 Identification of the species’ critical habitat

The Spotted Owl requires habitat for nesting, roosting, foraging and safe movement (see Section 3.3 – Needs of the Spotted Owl). Some mature and old-growth stands already possess the attributes required to support these functions, and some previously-disturbed habitat has the potential to acquire the necessary attributes within the 50-year timeframe needed to meet the population and distribution objective. A 400-m area surrounding nesting areas must also be protected from acoustic disturbance during the breeding season to ensure that acoustic disturbance does not result in loss of breeding habitat function. The critical habitat required by the Spotted Owl for recovery is therefore comprised of two subtypes:

1. Core critical habitat: habitat that either already possesses, or will develop (within a 50-year period), the features required by the owls to successfully nest, roost, forage and move safely
2. Acoustic critical habitat: habitat surrounding nesting areas that functions to maintain the acoustic environment within those areas during the breeding season

The geospatial areas that may contain critical habitat for the Spotted Owl are presented in Figures 4-9. Within these geospatial areas, critical habitat is identified wherever the following biophysical attributes occur.

Biophysical features and attributes of critical habitat

A description of the known biophysical features and attributes of the species’ habitat that are required to support life-cycle processes (functions) are summarized in Section 3.3, Needs of the Spotted Owl, and form the basis of the biophysical attribute description in Table 5 below.

Within the geospatial areas mapped as core critical habitat only unsuitable areas that do not possess the features and attributes required by the Spotted Owl at any time - either currently, or within the 50-year recovery timeframe - are excluded from identification as critical habitat. Examples of excluded areas include cultivated and/or landscaped areas, buildings, roads and artificial surfaces, or forested areas that have been recently harvested or subject to stand-destroying disturbance (for example, catastrophic fire), and so will not acquire the critical features and attributes of critical habitat within the 50-year recovery timeframe (see Table 2 for stand age thresholds specific to each sub-region).

7.1.1 Information and methods used to identify critical habitat

The location and spatial configuration of critical habitat is based on three principle assumptions:

• Quantity:
  • Minimum starting polygon size: to support foraging and nesting, noting that the species’ arboreal prey has a home range size of ~10 ha (Sutherland et al. 2007), core critical habitat must be configured around nesting class habitat polygons that are at least 10 ha in size
  • Overall core critical habitat area: to support the long-term population objective, the summed area of core critical habitat identified must be sufficient to:
    • support the home ranges of at least 125 pairs^{Footnote 14} of owls, noting that the mean amount of habitat to support a pair’s home range is estimated at 3010, 2224, and 1907 ha for the Maritime, Sub-maritime, and Continental sub-regions, respectively, and that adjacent home ranges may overlap up to 25% (Chutter et al. 2004 and 2007; Sutherland et al. 2007); and
    • account for up to 207,800 ha of habitat being impacted by fire within the 50-year recovery period (see Section 4.1)
• Support for all critical life functions (that is, biological value): To support all critical life functions for a recovering population, habitat must be prioritized for inclusion within the core critical habitat geospatial area based on its:
  1. contribution to a core patch that can support multiple home ranges and enable successful nesting, roosting, foraging, and safe movement within the patch:
     1. vicinity/degree of connectivity to recovery origins (existing locations and proposed re-introduction sites) or historical anchors (historical locations of resident birds)
     2. proportion of nesting class habitat; and
     3. size; or
  2. contribution to a potential connective corridor that can enable safe movement between core patches
• Representation across the three ecological sub-regions: To restore pre‑human-impact patterns of representation, critical habitat must be identified across all the three ecological sub-regions within the species’ historical range (Maritime, Sub-maritime, Continental)

The geospatial delineation process summarized below aims to create a well connected critical habitat network large enough to support 125 pairs, accounting for home range overlap and anticipated fire impacts, prioritizing habitat with the potential to support all critical life functions and restore pre-human-impact patterns of representation. The geospatial delineation process is founded upon chapter 6 of the integrated population and habitat modelling framework developed under the direction of CSORT (Sutherland et al. 2007). It is summarized below and outlined in greater detail in an accompanying technical document (available upon request).

The information used in the geospatial delineation of critical habitat for the Spotted Owl includes:

1. provincial VRI mapping (2018 version)
2. a Spotted Owl caurina subspecies habitat suitability classification produced by CSORT to be applied to VRI (Table 2)
3. a 50-year future projection of VRI (BC MFLNRORD 2019)
4. a least-cost/resistance landscape created through applying habitat-specific cost categories^{Footnote 15} to VRI polygons
5. a set of contiguous habitat clusters created through:
   1. applying a connectivity analysis to link all ≥ 10-ha nesting class polygons via least-cost pathways (based on the resistance landscape)
   2. selecting all habitat (either nesting class or foraging class) from the 50-year future projected VRI that intersects the least cost pathways; and
   3. dissolving polygons to create discrete clusters
6. origins/anchors of recovery comprised of:
   1. habitat occurring within the estimated maximum home range area of extant and historical locations of resident Spotted Owls, both within Canada (I. Blackburn, pers. comm. 2021) and in northern Washington; and
   2. habitat occurring within the estimated maximum home range area of the currently-proposed re-introduction locations for captive-bred Spotted Owls (I. Blackburn, pers. comm. 2021); and
7. potential connective corridors created through:
   1. applying a connectivity analysis to link all origins/anchors of recovery via least‑cost pathways (based on the resistance landscape); and
   2. selecting all habitat (either nesting class or foraging class) from the 50-year future projected VRI that is located within 500 m of a least-cost pathway

A summary of the geospatial delineation process is as follows:

1. Merge origins/anchors with any contiguous habitat clusters that intersect them to delineate origin/anchor habitat patches. Retain those that contain enough habitat to support at least one home range, within an area no larger than the maximum home range area estimated for that sub-region (see Section 3 - Species Needs)
2. Assess the biological value of the contiguous habitat clusters occurring outside of origin/anchor habitat patches and potential connective corridors
3. Build core critical habitat that will accommodate 125 home ranges (accounting for 25% overlap between adjacent ranges), enable safe movement between origin patches, and remain sufficient to support home range and safe movement targets after accounting for anticipated fire impacts (up to 207,800 ha; see Section 4.1 - Threats):
   1. include all functional^{Footnote 16} origin/anchor habitat: 272,793 ha (125 home ranges + ~65,000 ha towards fire impacts);
   2. include all functional¹⁶ potential corridor habitat linking origins/anchors: 99,585 ha (safe movement + fire impacts); and
   3. include additional contiguous habitat clusters occurring outside of origin/anchor and corridor habitat, by biological value score, until the fire impact target is met: 43,387 ha
4. Build acoustic critical habitat to counter acoustic disturbance within nesting areas:
   1. delineate nesting areas as all habitat polygons intersecting a 500-m area around nest sites (Blackburn et al. 2009); and
   2. establish a 400-m (horizontal distance) acoustic influence zone around the delineated nesting area(s)
5. Apply critical habitat sub-type classifications:
   1. designate all habitat identified through steps 1-3 as core critical habitat; and
   2. designate the habitat identified through step 4 as acoustic critical habitat

7.1.2 Geospatial Location of Areas Containing Critical habitat

Critical habitat for Spotted Owl is identified within three sub-regions in B.C. (Figures 4-9):

• overview map summary (all sub-regions): Figure 4
• maritime sub-region: Figure 5
• sub-maritime sub-region: Figures 6-8
• continental sub-region: Figure 9

The 10 km x 10 km UTM grid overlay shown on these figures is a standardized national grid system that highlights the general geographic area containing critical habitat, for land use planning.

Figure 4. Overview of the critical habitat for the Spotted Owl within B.C. Critical habitat is represented by the yellow shaded and black outlined polygons where the criteria and methodology set out in this section are met. The area below the hatched line is the U.S.A. land base.

Figure 5. Critical habitat for the Spotted Owl within the Maritime sub-region is represented by the yellow shaded polygons where the criteria and methodology set out in this section are met. The 10 km x 10 km UTM grid overlay shown on this figure is a standardized national grid system that indicates the general geographic area containing critical habitat. Federal Protected Areas that overlap with critical habitat are also shown.

Figure 6. Critical habitat for the Spotted Owl within the northern portion of the Sub-maritime sub-region is represented by the yellow shaded polygons where the criteria and methodology set out in this section are met. The 10 km x 10 km UTM grid overlay shown on this figure is a standardized national grid system that indicates the general geographic area containing critical habitat.

Figure 7. Critical habitat for the Spotted Owl within the central portion of the Sub-maritime sub-region is represented by the yellow shaded and black outlined polygons where the criteria and methodology set out in this section are met. The 10 km x 10 km UTM grid overlay shown on this figure is a standardized national grid system that indicates the general geographic area containing critical habitat.

Figure 8. Critical habitat for the Spotted Owl within the southern portion of the Sub-maritime sub-region is represented by the yellow shaded and black outlined polygons where the criteria and methodology set out in this section are met. The 10 km x 10 km UTM grid overlay shown on this figure is a standardized national grid system that indicates the general geographic area containing critical habitat. The hatched line in the southern extent of the map is the border with the Continental U.S.A.

Figure 9. Critical habitat for the Spotted Owl within the Continental sub-region is represented by the yellow shaded polygons where the criteria and methodology set out in this section are met. The 10 km x 10 km UTM grid overlay shown on this figure is a standardized national grid system that indicates the general geographic area containing critical habitat.

7.2 Schedule of studies to identify critical habitat

The following schedule of studies (Table 6) is required to complete the identification of acoustic critical habitat for the Spotted Owl.

7.3 Activities likely to result in the destruction of critical habitat

8. Measuring progress

The performance indicators presented below provide a way to define and measure progress toward achieving the population and distribution objectives.

1. Human-caused threats that would cause further loss of habitat needed for recovery (that is, the critical habitat) have been ceased
2. At least 50 captive-bred Spotted Owls have been reintroduced to the wild by 2032, and at least 10 have survived to become resident adults
3. Annual Barred Owl surveillance has taken place within all sites occupied by Spotted Owls and/or where reintroductions are planned, and all detected Barred Owls have been removed

9. Statement on action plans

One or more action plans for the Spotted Owl will be published on the Species at Risk Public Registry within 5 years of the finalization of this document.

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11. Personal communications

Ian Blackburn. Manager, Resource Stewardship for Ecosystems - B.C. Ministry of Forests, Lands, Natural Resource Operations and Rural Development. 2021.

Joseph Buchanan. Wildlife Biologist/Natural Resource Scientist – Washington Department of Fish and Wildlife. 2019.

Joel Gillis. Spotted Owl Biologist – B.C. Ministry of Forests, Lands, Natural Resource Operations and Rural Development. 2019.

Joel Gillis. Spotted Owl Biologist – B.C. Ministry of Forests, Lands, Natural Resource Operations and Rural Development. 2020.

Joel Gillis. Spotted Owl Biologist – B.C. Ministry of Forests, Lands, Natural Resource Operations and Rural Development. 2021.

Government of B.C representatives, B.C. Minister of Water, Lands and Natural Resource Operations. to Honourable Stephen Guilbeault, Minister of Environment and Climate Change. 2023.

Joanna Hirner. Conservation Specialist – B.C. Parks. 2020.

Appendix A: Effects on the environment and other species

A strategic environmental assessment (SEA) is conducted on all SARA recovery planning documents, in accordance with the Cabinet Directive on the Environmental Assessment of Policy, Plan and Program Proposals^{Footnote 17}. The purpose of a SEA is to incorporate environmental considerations into the development of public policies, plans, and program proposals to support environmentally sound decision-making and to evaluate whether the outcomes of a recovery planning document could affect any component of the environment or any of the Federal Sustainable Development Strategy’s^{Footnote 18} (FSDS) goals and targets.

Recovery planning is intended to benefit species at risk and biodiversity in general. However, it is recognized that strategies may also inadvertently lead to environmental effects beyond the intended benefits. The planning process based on national guidelines directly incorporates consideration of all environmental effects, with a particular focus on possible impacts upon non‑target species or habitats. The results of the SEA are incorporated directly into the strategy itself, but are also summarized below in this statement.

Conservation of habitat for the Spotted Owl will benefit a multitude of vertebrate, invertebrate, and plant species that use mature and old-growth coniferous forests. Harper and Milliken (1994) concluded there were approximately 71 species of vertebrates closely associated with late‑successional and old forests within the range of the Spotted Owl in Canada (four amphibians, 34 birds, 17 mammals, and 16 fish). Examples of other species at risk whose habitats overlap with those of Spotted Owls include Marbled Murrelet (Brachyramphus marmoratus), Northern Goshawk (Accipiter gentilis), and Western Screech-Owl (Megascops kennicottii) kennicottii and macfarlanei subspecies. The large landscapes required to manage and conserve populations of Spotted Owls lend themselves to application of ecosystem-based approaches to forest management. The restoration and conservation of habitat for the Spotted Owl will help maintain functioning late-successional forest ecosystems, and help regulate water and nutrient cycles. Further, many of the old-growth stands conserved for the Spotted Owl are likely to function as refugia as climate change-mediated disturbances increase in frequency and extent. Protection of these areas for Spotted Owls will also improve the climate change resilience of other old-forest-dependent species.

Barred Owls are also known to compete with or prey upon a number of other native species, including species at risk. Predation by Barred Owls is one of the highest-level IUCN-CMP threats for Western Screech-Owl kennicottii and macfarlanei subspecies, the ranges of which overlap significantly with that of the Spotted Owl. Control of Barred Owls within the Spotted Owl range will therefore also support recovery of Western Screech-Owl.