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BC Conservation Data Centre: Conservation Status Report

Spizella breweri breweri
Brewer's Sparrow, breweri subspecies

 
Scientific Name: Spizella breweri breweri
English Name: Brewer's Sparrow, breweri subspecies
   
Provincial Status Summary
Status: S2S3B
Date Status Assigned: April 29, 2018
Date Last Reviewed: April 28, 2025
Reasons: The subspecies faces ongoing threats from loss and degradation of the sagebrush-steppe habitat upon which it depends. Most of the population is concentrated in a relatively small area of the southern Okanagan which is subject to habitat loss due to urban development, agricultural pressures and wild fires.
 
Range
Range Extent: EF = 5,000-200,000 square km
Range Extent Estimate (km2): 24,347
Range Extent Comments: North American distribution extends from southern BC and Alberta, and sw. Saskatchewan, through the Great Basin and northern Mojave Desert systems in the US (Rotenberry et al. 2020). Within British Columbia, it is restricted to the Southern Interior Ecoprovince, with the subspecies range extending from the southern Okanagan valley north to Kamloops, Ashcroft, the Chilcotin River, Riske Creek and perhaps as far north as Dog Creek (Campbell et al. 2001) resulting in a range extent of 24,347 square km. However, the area where the species is reliably found every year is smaller than this, being largely restricted to the Okanagan Valley. Mahony (2003) estimated the total area of breeding habitat within the BC Okanagan and Similkameen valleys as 2,700 km2. This subspecies has been detected at elevations between 340 - 1,860 m ASL (MOE 2004). Breeding is largely restricted to shrub-steppe sagebrush habitats dominated by live sagebrush with a mixed bunchgrass and forb understorey. Campbell et al (2001) and Starzomski (2015c) both point out the uncertainty of assigning subspecies to higher elevation records from the southern part of the province, however high elevation nesting of this subspecies has been seen elsewhere and confirmed as breweri (e.g., Colorado) (Walker 2023). In addition, there are differences in the timing of migration with the two subspecies in southern British Columbia, breweri earliest records are the second week of April whereas the birds in the East Kootenay (taverneri) don't start arriving until the third week of May (eBird, accessed Mar 2024).
Area of Occupancy (km2): E = 26-125
 
Occurrences & Population
Number of Occurrences: BC = 6 - 80
Comments: There are 18 element occurrences mapped by the BC CDC (March 2024). There are also an additional four sites with suspected breeding in the Thompson Basin (Sarell and McGuiness 1996). Based on an additional observations (e.g., near Merritt and Lillooet), other breeding sites may exist, particularly in the Thompson region. Habitat suitability has been modeled for the Okanagan but not for the Thompson region; however, habitat models alone may not provide an accurate estimate of suitable habitat due to territory clustering as a result of conspecific presence (Harrison et al. 2009).
Number of Occurrences with Good Viability / Ecological Integrity: U = Unknown
Comments: It is likely that element occurrences within existing protected areas have good viability, providing sagebrush cover is adequately maintained. Increasingly wild fires are burning mature sagebrush habitats in protected areas.
Number of Occurrences Appropriately Protected & Managed: D = 13 - 40
Comments: Element occurrences within existing protected areas may have good viability, provided shrub/sagebrush cover (and adjacent aspen stands) are adequately maintained. Some breeding habitat occurs within existing protected areas and private conservation lands. These include South Okanagan Grasslands Protected Area, White Lake Grasslands, and Nature Conservancy of Canada?s Sage and Sparrow Conservation Area.
Population Size: BD = 50 - 2,500 individuals
Comments: The estimates of the breweri subspecies in British Columbia range from 81 pairs to 1,184 pairs (Sarrell and McGuinness 1996, Mahony 2003).
 
Threats (to population, occurrences, or area affected)
Degree of Threat: C = Medium
Comments: The primary threat is habitat loss through urban and agricultural development. This subspecies is also threatened by overgrazing and incompatible grassland management (e.g. pesticide spraying, irrigation or prescribed burning or chaining to eliminate sagebrush). Fire suppression in sagebrush habitat, leading to tree encroachment, are incompatible with maintaining quality breeding habitat (Krannitz and Rohner 2000). On the other hand, recent high intensity wild fires have destroyed mature sagebrush habitats. Water diversions that alter hydrology in aspen stands adjacent to breeding habitat are also considered a threat. Assigned threat impact is based on Cindy McCallum and Rick Howie's 2015 threat assessment, modified by Fraser, D.F. (2024).
 
Trend (in population, range, area occupied, and/or condition of occurrences)
Short-Term Trend: F = Decline of 10-30%
Comments: Generation time for this species has been estimated by Bird et al. (2020) as 2.1 years, so the short term trend is for a period of ten years. Breeding Bird Survey analysis indicates a short term decline (2011 to 2021) of -27.8% for British Columbia. Note however that reliability of this estimate is characterized as "low" with only 10 routes reporting the species (Smith et al. 2023). This is similar to the North America wide decline estimate (Rotenberry et al. 2020). Surveys up to 1992 at White Lake indicated the area consistently supported 20 pairs (Sarell and McGuinness 1996). Widespread fires in British Columbia in the summer of 2023 burned some older sagebrush habitats but the total impact of this habitat loss has not been quantified.
Long-Term Trend: D = Decline of 50-70%
Comments: Breeding Bird Surveys (BBS) have shown significant population declines of Brewer's Sparrow (Rotenberry et al. 1999). In the US, population declines have been greater than 50% since the 1980s (Holmes and Johnson 2005). The decline in the area, extent and quality of sagebrush-steppe habitats suitable for S. b. breweri is ongoing but unquantified in British Columbia. Dyer and Haney (2019) estimated the loss of sagebrush habitat as greater than 50% from historical levels.
 
Other Factors
Intrinsic Vulnerability: Rank Factor not assessed
Environmental Specificity: A=Very narrow. Specialist or community with key requirements scarce.
Comments: Largely tied to Sagebrush (Artemesia tridentata) and Purshia dominated habitats in the southern Interior.
Other Rank Considerations:
 
Information Gaps
Research Needs:
Inventory Needs:
 
Stewardship
Protection:
Management:
 
Version
Author: Fraser, D.F. (2024), Ramsay, R and Dulc , S. (2018), J. Cooper, J, (2016)
Date: February 17, 2024
 
References
B.C. Conservation Data Centre. CDC iMap. B.C. Ministry of Environment Victoria, BC. Available: http://maps.gov.bc.ca/ess/sv/cdc/
Bird, J., R. Martin, H.R. Akçakaya, et al. 2020. Generation lengths of the world?s birds and their implications for extinction risk. Conservation Biology 34:1252?1261.
Bradley, C. A., Gibbs, S. E. J. and Altizer, S. 2008. URBAN LAND USE PREDICTS WEST NILE VIRUS EXPOSURE IN SONGBIRDS. Ecological Applications, 18: 1083?1092. doi:10.1890/07-0822.1
British Columbia Ministry of Water, Land and Air Protection. 2004. "Sagebrush" Brewer's Sparrow (Spizella breweri breweri) in Accounts and Measures for Managing Identified Wildlife ? Accounts V. 2004. B.C. Ministry of Water, Land and Air Protection, Victoria, B.C. 
Available: http://www.env.gov.bc.ca/wld/frpa/iwms/accounts.html (accessed Oct 16 2017).
Cannings, R.A., R.J. Cannings, and S.G. Cannings. 1987. Birds of the Okanagan Valley, B.C. Royal B.C. Mus., Victoria, BC. 420pp.
Cannings, R.J. 1998. The Birds of British Columbia - a taxonomic catalogue. B.C. Minist. Environ., Lands and Parks, Wildl. Branch, Victoria, Wildl. Bull. B-86. 266pp.
eBird. ND. eBird: an online database of bird distribution and abundance [web application]. eBird, Cornell Lab of Ornithology, Ithaca, N.Y.
Gebauer, M. 2004. ?Sagebrush? Brewer?s Sparrow Spizella breweri breweri. Accounts and Measures, Identified Wildlife Strategy.
Mahony, N. A., P. G. Krannitz and K. Martin. 2006. Seasonal fecundity of Sagebrush Brewer?s Sparrow (Spizella breweri breweri) at the northern edge of its breeding range. Auk 123: 512-523.
Mahony, N.A. 2003. Reproductive ecology and population viability of Brewer's Sparrows at the northern edge of the breeding range.  Ph.D. Thesis, Univ. of B.C., Vancouver. 126pp.
Ministry of Environment, Lands and Parks. 1999. Wildlife at risk atlas for the Southern Okanagan. Penticton, BC.
Ministry of Water Land and Air Protection. Environmental Stewardship Division. 2003. Okanagan Region Management Direction Statement for Chopaka East site of South Okanagan Grasslands protected area. 22pp.
NatureServe. ND. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org.
Rotenberry, J. T., M. A. Patten, and K. L. Preston. 2020. Brewer's Sparrow (Spizella breweri), version 1.0. In Birds of the World (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.
Sarell, M.J., and K.P. McGuinness. 1996. Status of the Brewer's Sparrow in British Columbia. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. Working Rep. WR-77. 22pp.
South Okanagan Regional Growth Strategy.  Bylaw 2421, 2007 ? Schedule ?A?
Starzomski, B. 2015c. Brewer's Sparrow in Davidson, P.J.A., R.J. Cannings, A.R. Couturier, D. Lepage, and C.M. Di Corrado (eds.). The Atlas of the Breeding Birds of British Columbia, 2008-2012. Bird Studies Canada. Delta, B.C.
Walker, B.L. 2023. Citizen Science Project: Breeding Distribution of Brewer?s Sparrows in Alpine Areas of Colorado. Colorado Parks and Wildlife.
 

Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.

Suggested Citation:

B.C. Conservation Data Centre. 2024. Conservation Status Report: Spizella breweri breweri. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 6, 2026).