Recent risk assessment updates for bird species in Canada

By Pete Davidson, Vice President Science, Birds Canada and member of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) Birds Specialist Subcommittee, Dr. Louise Blight, Adjunct Associate Professor, School of Environmental Studies, University of Victoria and Co-Chair, COSEWIC Birds Specialist Subcommittee, Dr. Andrew Horn, Dalhousie University and Co-Chair, COSEWIC Birds Specialist Subcommittee.

Five well-loved bird species including the Snowy Owl and Bobolink, had their conservation status change last year. Here’s what those changes mean, why they’re happening, and how action can make a real difference.

Background on Assessment

Assessing which species are at risk of extinction is an important indicator of nature’s health, and a key tool for catalyzing conservation action and policy change. In Canada, the Species at Risk Act (SARA) lists at-risk species and provides for their recovery based on bi-annual assessments by an independent scientific body, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Globally, extinction risk to all bird species is assessed annually by BirdLife International, the official Red List Authority for birds for The International Union for the Conservation of Nature (IUCN) Red List of Threatened Species™.

The IUCN Red List and COSEWIC criteria assessment processes are very similar, but use different terms for categories of risk. COSEWIC Special Concern, Threatened and Endangered align very closely with IUCN Near Threatened, Vulnerable, and Endangered, respectively. Nonetheless, COSEWIC assesses species’ status solely within Canada, so discrepancies often arise if Canada constitutes only a portion of a species’ global range. Birds Canada staff feed the results from Canadian monitoring into the IUCN process via Globally Threatened Bird Forums and other channels.

For birds in particular, volunteerism is crucial to this process. Volunteers who collect long-term monitoring data, like those of you participating in Birds Canada programs, generate much of the information that goes into risk assessment. If you have ever participated in a national or regional initiative, like the Breeding Bird Survey, Christmas Bird Count, Breeding Bird Atlas, Marsh Monitoring Program, Coastal Waterbird Survey, High Elevation Landbird Program, or the Canadian Migration Monitoring Network, then you have contributed, and we sincerely thank you!

COSEWIC Updates for Five Species in Canada

Snowy Owl Bubo scandiacus

In 2025, COSEWIC assessed the status of one bird species, along with 48 other species, including mammals, fishes, arthropods, plants, and mosses. This iconic and culturally important Arctic owl is for the first time nationally assessed as Threatened, based primarily on Christmas Bird Count (CBC) data across the southern part of its North American range, which show a 42.6% rate of decline over the last three generations (24 years). The decline shown by CBC data is consistent with a recently-published worldwide estimate based on nest counts at long-term (1988-2020) study sites on Snowy Owl breeding grounds in Russia, Greenland, Alaska, and Canada (Nunavut); these range-wide data show a decline greater than 30%, the threshold for an assessment of Threatened.

The species continues to be listed as IUCN Vulnerable as a result, and was recently declared Extinct as a breeding bird in Sweden. Indigenous knowledge from two northern Canadian regions (Baffin Island and the Yukon coast) also reports this owl is less frequently encountered than it used to be, likely due to warming climate conditions. Other threats in Canada include highly pathogenic avian influenza, poisoning with anticoagulant rodenticides, collisions, and electrocution.

IUCN Red List Updates

The following four species saw IUCN status changes this year.

Greater Sage-Grouse Centrocercus urophasianus

This spectacular but often secretive denizen of the Great Plains and Great Basin is uplisted to Vulnerable globally, due to a long-term, continuing rapid decline and contraction in range as its sagebrush habitat is lost and degraded. The main drivers are agriculture and development, but increasing fire frequency and intensity are also contributing, facilitating conifer and invasive grass encroachment. In Canada, it is Endangered, but notably, new Key Biodiversity Area designations and long-term recovery efforts show reason for cautious optimism.

Greater Sage-Grouse - Sean Jenniskens - WY (3).JPG

Photo: Sean Jenniskens

Bobolink Dolichonyx oryzivorus

This long-distance migrant of grassland habitats is uplisted to IUCN Near Threatened because it is estimated to be declining at a rate of 22-28% over the last decade, based on the Breeding Bird Survey and eBird Status and Trends data. The decline is likely a result of land-use change across its wide range, and other more localized threats. In Canada, Bobolink is currently listed as Threatened, but was reassessed by COSEWIC as Special Concern in 2022 and is being considered for downlisting under SARA as a result.

Photo: Jack Belleghem

Olive-sided Flycatcher Contopus cooperi

Birds Canada’s Avian Ambassador from 2024 has been downlisted from Near Threatened to Least Concern at the global level. Whilst this reads like good news, it is not a genuine status improvement; the species continues to decline, but not at rates that are close to thresholds for Vulnerable. For the same reason, this species was recently downlisted from Threatened to Special Concern in Canada.

Olive-sided Flycatcher 3 - BC - Ian Burgess.jpg

Photo: Ian Burgess

Brewer’s Blackbird Euphagus cyanocephalus

The Breeding Bird Survey, and eBird Status and Trend data, show declines estimated at 12-24% over the past ten years, part of a consistent long-term decline shown by the Breeding Bird Survey such that this species has seen a cumulative loss of about three-quarters of its population since 1970. This 10-year rate of population change comes close to the threshold for Vulnerable, and so the species is assessed as Near Threatened, for the first time. Threats include incidental shooting and poisoning from pest control measures in some areas.

Brewer's Blackbird - AB - Yousif Attia.JPG

Photo: Yousif Attia

How you can help, and learn more

To check on the status of your favourite Canadian birds, The State of Canada’s Birds has all the designations from global to Canadian risk assessments in one place. Birds Canada is grateful to all our volunteers, supporters, and conservation partners who are working to improve the outlook for bird species in Canada. To find out how you can help birds of conservation concern and keep our common birds common, please take a look at Your Guide to Helping Canada’s Birds