Species Profile

Williamson's Sapsucker

Scientific Name: Sphyrapicus thyroideus
Taxonomy Group: Birds
COSEWIC Range: British Columbia
COSEWIC Assessment Date and Status Change: November 2017
COSEWIC Status: Endangered
COSEWIC Status Criteria: C2a(ii)
COSEWIC Reason for Designation: This migratory woodpecker depends on old-growth coniferous and mixed forests in the Southern Interior of British Columbia, with fewer than 1000 individuals breeding in two Canadian subpopulations. Its distribution is largely limited by the availability of large nest-trees, mostly several hundred years old. The main threat to this species is logging and forest harvesting, including removal of dangerous trees for worker safety, forest fires and fire suppression. Lower impact threats are housing and urban development, ranching, and renewable energy development. Despite recent forest harvest regulations in British Columbia intended to protect its nesting habitat, breeding numbers are anticipated to decline further.
COSEWIC History of Status Designation: Designated Endangered in May 2005. Status re-examined and confirmed in November 2017.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2006-08-15

Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.

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Image of Williamson's Sapsucker

Williamson's Sapsucker Photo 1



Two subspecies of Sphyrapicus thyroideus are recognized, namely S. t. thyroideus and S. t. nataliae. Since it is virtually impossible to tell them apart from simple physical characteristics, this profile deals with the species overall. Both subspecies are present in Canada.



The Williamson’s Sapsucker is an average-sized woodpecker, its total length ranging from 21 to 25 cm. Unlike other woodpeckers, the male and female have very different plumage. The female’s plumage is mainly brown and black, whereas the male’s plumage is shiny black, with a bold white bar on its wing, a white stripe on its cheek and a smaller one above its eye. It is also distinguishable by its yellow belly and a small red patch on its throat. The female has a brownish head, a black chest and many brown and black bars on its wings, sides and tail. Juveniles resemble the adults, except that the males do not yet have the red patch on their throat and the females do not have the black chest.


Distribution and Population

The Williamson’s Sapsucker is found mainly in the mountains of western North America, from southern British Columbia to the southern United States and northern Baja California in Mexico. In Canada, the species nests solely in southern British Columbia. Based on known nesting sites, the total population has been divided into five geographically separate populations: four populations of the subspecies thyroideus and one population of the subspecies nataliae. In Canada, the two subspecies occupy completely separate regions. The subspecies thyroideus nests from British Columbia’s Manning Provincial Park, at the Canada–United States border, to the areas around Lytton, Cache Creek and Kamloops to the north, and the drylands of the Okanagan Valley as far as Greenwood to the east. The subspecies nataliae is limited to the far southeast of the province. It is found in the broad valley that cuts through the Rockies to Cranbrook, Kimberley and Whiteswan Lake to the north, and in the Flathead River valley. The total number of Williamson’s Sapsuckers in Canada is probably around 430 breeding adults, only 10 of which are the subspecies nataliae. Since the Williamson’s Sapsucker is relatively rare, the data are insufficient for identifying trends in its Canadian populations. However, it is conceivable that the species is in decline because the environments it can use for habitat are shrinking. In the only region where trends have been identified, namely Oregon, it was estimated that the total number of Williamson’s Sapsuckers declined at an annual rate of 3.3% from 1980 to 2003.



The Williamson’s Sapsucker nests in mountain coniferous forests, at medium or high altitudes. It can also nest in mixed forests, where it often selects trembling aspens for nesting. In British Columbia, the only dense populations of the Williamson’s Sapsucker seem associated with forests of veteran western larch, over 200 years old. In fact, most individuals or nests have been seen in large stands of western larch, or less than 200 m from them, at an altitude of 1000 to 1400 m. A smaller percentage of breeding adults nest in ponderosa pine forests or stands of trembling aspens near ponderosa pine or western larch forests, generally at an altitude of between 800 and 1100 m. Nearly 57% of Williamson’s Sapsucker nests are found in dense forest. And even when the birds place their nests in sparser stands of trees, they are never more than 40 m from a dense forest stand where they go to feed. In the habitat where it breeds, the Williamson’s Sapsucker must find trees in which it can dig holes or that already have cavities where it can place its nest. Its habitat must also provide it with living conifers from which it can draw sap, and other standing trees, alive or dead, from which it can retrieve carpenter ants to eat and feed its young. The old-growth western larch forest that is home to the greatest concentration of Williamson’s Sapsuckers provides all these elements. In particular, the large veteran larches that characterize it bear traces of many fires and are heavily affected by heart rot, providing places where the sapsucker can readily dig its nest. Apparently nowhere else are there other plots of land with western larches that big and that old. This forest appears to be unique.



The Williamson’s Sapsucker is a migratory bird. It is found in Canada only at breeding time, which is mid-March to mid-September. When the males arrive in spring, they start establishing their territory. The females begin to appear one or two weeks later. Formed almost right away, the pairs dig their nests in a tree trunk or standing dead tree, or they settle in an unused cavity. In a season, they have one clutch, which usually contains 4 to 6 eggs. From 26 to 33 days after they are born, the juveniles take their first flight. Very little is known about the breeding success of the species and dispersal of the young. The subspecies thyroideus prefers to make its nest in conifers. In British Columbia, it specifically selects western larches. In the southern Rockies, the subspecies nataliae most often builds its nest in trembling aspens. If there are no aspens with the required qualities, it chooses the ponderosa pine. But if the nest is built in a trembling aspen, the adults feed primarily in nearby conifers. Before the eggs hatch, the Williamson’s Sapsucker feeds primarily on conifer sap. During their time in the nest, the parents and young eat mainly carpenter ants and, occasionally, other insects. In winter, small fruits are added to the menu. In western North America, the Williamson’s Sapsucker is prey to raptors, including the Sharp-shinned Hawk, Cooper’s Hawk and Northern Goshawk. Included among the raiders of this species’ nests are the red squirrel, long-tailed weasel, black bear, snakes and probably the deer mouse and House Wren. There is no information on the breeding success or lifespan of Williamson’s Sapsuckers in Canada.



In Canada, the Williamson’s Sapsucker is threatened primarily by the limited quantity of suitable nesting places, namely old-growth western larch forests, which continue to shrink due to forestry and land clearing. In the early 1990s, the main Williamson’s Sapsucker population of Okanagan-Greenwood could use only 19.5% of the 594 km² area it occupied. By 2004, this proportion had dropped to roughly 15%. In that area, the logging rate is about 1% of the forest area per year, and most stands targeted are old-growth stands of the type occupied by the Williamson’s Sapsucker. It is estimated that by 2014, cutting will destroy up to 53% of the current area suitable for the species. Most cutting done in the area does not leave enough trees standing to meet the species’ needs, and the veteran larches that the Williamson’s Sapsucker prefers for nesting and gathering ants will not be replaced for a long time. Moreover, the Williamson’s Sapsucker does not frequent logged areas if there is not an old-growth western larch or Douglas-fir forest nearby. Without protection measures, the suitable nesting environments for Canada’s largest population of the species could be virtually eliminated by 2024, or at least reduced to the point of being unable to support a viable population.



Federal Protection

The Williamson's Sapsucker is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

The Williamson’s Sapsucker is protected under the federal government’s Migratory Birds Convention Act, 1994. This statute prohibits the harming, killing or collecting of eggs, adults and young. The species is also protected by the British Columbia Wildlife Act. The only known nesting site of the subspecies nataliae is in a municipal park in the southeastern part of the province, where it benefits from a certain degree of protection.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.


Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for the Williamson's Sapsucker (Sphyrapicus thyroideus) in Canada
Status Final posting on SAR registry


Recovery Team

Williamson's Sapsucker Recovery Team

  • Megan Harrison - Chair/Contact - Environment Canada
    Phone: 604-350-1989  Fax: 604-946-7022  Send Email


Recovery Progress and Activities

Summary of Progress to Date A recovery team for the Williamson’s Sapsucker has been established. COSEWIC assessed the Williamson’s Sapsucker as endangered based on estimates of historic and projected rates of habitat loss and fragmentation from timber harvesting. The Williamson’s Sapsucker’s recovery strategy is being developed. It will provide a framework for recovery through development of recovery goals and objectives, including population, distribution, and research objectives. The recovery team will complete a schedule of studies to identify critical habitat in an upcoming action plan, as sufficient biological information is not available to immediately describe critical habitat. Action planning will take place concurrently with the development of the recovery strategy and will be informed by the emerging recovery framework being developed by the recovery team. Summary of Research/Monitoring Activities From 1995 to the present, the British Columbia Ministry of Environment (BC MoE) has conducted extensive call-playback surveys in potentially suitable habitat throughout a large proportion of range of the sapsucker in Canada. In 2006, BC MoE, with the support of Environment Canada, increased the survey effort and collected vegetation data, which will allow for better characterization of sapsucker habitat. First Nations interviews elders and other knowledgeable advisors on Native reserves to map the potential habitats of the Williamson’s Sapsucker. Summary of Recovery Activities BC Ministry of Environment has added the Williamson’s Sapsucker to the list of Identified Wildlife under the BC Forest and Range Practices Act. This designation permits BC to create Wildlife Habitat Areas (WHAs) on provincial crown land, which are to be managed for the conservation of Identified Wildlife. The actual designation of WHAs for Williamson’s Sapsucker will be a component of the action planning process. Key stakeholders within the forest industry are involved in this initiative. URLs The Birds of North America Online – Species Profilehttp://bna.birds.cornell.edu/BNA/account/Williamsons_Sapsucker/


PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

13 record(s) found.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Williamson's Sapsucker (Sphyrapicus thyroideus) in Canada (2018-10-15)

    Williamson’s Sapsucker is a medium-sized woodpecker with no recognized subspecies. Unique among woodpeckers, the male Williamson’s Sapsucker (mostly black and white) and the female (mostly black and brown) exhibit strikingly different plumage. It is considered a sensitive indicator species because of its specific requirements for habitat with large trees that provide nest cavities and colonial ants on which to forage. It is a primary cavity excavator, making holes in trees that may be used by a variety of secondary cavity-using species. Note: This COSEWIC assessment was received by the Minister on October 15th, 2018.
  • COSEWIC assessment and status report on the Williamson's Sapsucker Sphyrapicus thyroideus in Canada (2005-05-01)

    The Williamson's Sapsucker, Sphyrapicus thyroideus, is a medium-sized woodpecker. Unique among woodpeckers, the male (mostly black and white) and the female (mostly black and brown) exhibit strikingly different plumage. There are two recognized subspecies, S. t. thyroideus and S. t. nataliae, both of which occur in Canada. However, there are no distinctive morphological features known that can reliably separate individuals of the two subspecies, so the subspecies have not been assessed separately in this report.

Response Statements

  • Response Statement - Williamson's Sapsucker (2019-01-11)

    This migratory woodpecker depends on old-growth coniferous and mixed forests in the Southern Interior of British Columbia, with fewer than 1000 individuals breeding in two Canadian subpopulations. Its distribution is largely limited by the availability of large nest-trees, mostly several hundred years old. The main threat to this species is logging and forest harvesting, including removal of dangerous trees for worker safety, forest fires and fire suppression. Lower impact threats are housing and urban development, ranching, and renewable energy development. Despite recent forest harvest regulations in British Columbia intended to protect its nesting habitat, breeding numbers are anticipated to decline further.
  • Response Statements - Williamson's Sapsucker (2005-11-15)

    This woodpecker is associated with mature larch forests in south-central British Columbia; less than 500 individuals breed in Canada. Habitat loss through forest harvest is estimated to have been 23% over the last 10 years and is projected to be about 53% over the next decade.

Recovery Strategies

  • Recovery Strategy for the Williamson’s Sapsucker (Sphyrapicus thyroideus) in Canada (2016-07-06)

    The Minister of the Environment is the competent minister for the recovery of the Williamson’s Sapsucker and has prepared this strategy, as per section 37 of SARA. It has been prepared in cooperation with the Government of British Columbia, environmental non-governmental organizations, industry stakeholders and the St. Mary’s Band of the Ktunaxa Nation. The Recovery Strategy for the Williamson’s Sapsucker was modified in June 2016 to replace Figure 3 (Critical habitat for the western area of occupancy).


COSEWIC Annual Reports

  • COSEWIC Annual Report - 2005 (2005-08-12)

    2005 Annual Report to the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
  • COSEWIC Annual Report 2017 to 2018 (2018-10-15)

    Over the past year COSEWIC assessed a total of 90 wildlife species and 11 of these were assigned a status of Not at Risk. Of these 90, COSEWIC re-examined the status of 38 wildlife species; of these, the majority (87%) were reassessed at the same or lower level of risk. To date and with the submission of this report, COSEWIC’s assessments now include 771 wildlife species in various risk categories including 338 Endangered, 183 Threatened, 228 Special Concern, and 22 Extirpated (i.e. no longer found in the wild in Canada). In addition, 18 wildlife species have been assessed as Extinct, and a total of 59 wildlife species have also been designated as Data Deficient and 197 have been assessed and assigned Not at Risk status.

Permits and Related Agreements

Consultation Documents

  • Consultation on Amending the List of Species Under the Species At Risk Act: November 2005 (2005-11-16)

    The Government of Canada proclaimed the Species at Risk Act (SARA) on June 5, 2003 as part of its strategy for the protection of wildlife species at risk. Attached to the Act is Schedule 1, the list of the species that receive protection under SARA, hereinafter referred to as the 'SARA list'. Canadians are invited to comment on whether all or some of the species included in this document should be added to the SARA list.
  • Consultation on Amending the List of Species under the Species at Risk Act: Terrestrial Species January 2019 (2019-01-15)

    The Government of Canada is committed to preventing the disappearance of wildlife species at risk from our lands. As part of its strategy for realizing that commitment, on June 5, 2003, the Government of Canada proclaimed the Species at Risk Act (SARA). Attached to the Act is Schedule 1, the list of the species provided for under SARA, also called the List of Wildlife Species at Risk. Extirpated, Endangered and Threatened species on Schedule 1 benefit from the protection afforded by the prohibitions and from recovery planning requirements under SARA. Special Concern species benefit from its management planning requirements. Schedule 1 has grown from the original 233 to 580 wildlife species at risk. Please submit your comments by May 13, 2019, for terrestrial species undergoing normal consultations and by October 14, 2019, for terrestrial species undergoing extended consultations. For a description of the consultation paths these species will undergo, please visit the Species at Risk (SAR) Public Registry website at: The Minister of the Environment's Response to Species at Risk Assessments.
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