BREWER’S SPARROW
SPECIES ACCOUNT
Species Data
Common Name:
“Sagebrush” Brewer’s Sparrow
Scientific Name:
Spizella breweri breweri
Species Code:
B-BRSP
BC Status:
Red-listed
Identified Wildlife Status:
Volume II
COSEWIC Status:
Project Data
Project Name:
Bella Vista / Goose Range Sensitive Ecosystems Inventory
Project Type:
Terrestrial Ecosystem Mapping
Area:
North Okanagan
Ecoprovince:
Southern Interior
Ecoregions:
Thompson-Okanagan Plateau
Ecosections:
Northern Okanagan Basin (NOB)
BGC Units:
IDFxh1
Map Scale:
1:20 000
Distribution
Provincial Range
Brewer's Sparrows occur in the Okanagan and Similkameen valleys (RBCM 1996), but are almost absent
north of Penticton (Cannings et al. 1987). Breeding generally occurs west of the Okanagan River from
the Marron Valley south to Kilpoola Lake, and may occasionally occur in other locations including
Vernon, Kamloops, Ashcroft, the Chilcotin River and Riske Creek (Campbell et al. 2001).
Highest concentrations of Brewer's Sparrows occur in sagebrush habitats in the Okanagan valley south of
Penticton, and in the Similkameen valley south of Keremeos, particularly White Lake and Richter Pass
(Cannings et al. 1987).
Elevation Range
Brewer's Sparrows have been documented from 350 to 1800 metres (BC Environment 1997). In BC, the
average elevation is 775 metres, with the greatest concentration around 900 metres (Harvey 1992; Sarell
and McGuinness 1996).
Distribution in the Project Area
One record from the study area (Willing 1970).
2/17/2016
Page 1 of 6
BREWER’S SPARROW
Ecology and Habitat Requirements
Brewer’s Sparrows arrive in BC in late April or May, and leave in late August or early September
(Cannings et al. 1987). Egg-laying occurs from May through July, with an average clutch size of three to
four eggs (Gebauer 2002). Multiple nesting is common, with 18% (n=176) of females fledging more
than one brood: 30 females raised two broods, and two females raised three broods (Mahony et al. 2002).
Hatching occurs from late May through July, and young fledge at six to nine days (Gebauer 2002).
Breeding territories are generally around 0.5 ha (Cannings et al. 1987). Brewer’s Sparrows are semicolonial and often breed in loose aggregations of two to 21 pairs, occupying areas from six to 225 ha
(Harvey 1992). Brewer's Sparrow response to human disturbances, such as road traffic and residential
developments is unknown (Sarell and McGuinness 1996).
Sagebrush habitats are used for breeding, often with nearby aspen copses or wetlands. By mid-July, after
young have fledged and adults have finished breeding, activity is generally restricted to sites that include
deciduous vegetation such as aspen and tall shrubs, rather than those dominated by sagebrush (Yu 2001).
Reproducing
Security/Thermal Habitat (Nesting)
Nesting occurs primarily in sagebrush habitats. Of 32 nests recorded by Krannitz and Gill (unpubl. data),
one occurred in antelope brush with the territory entirely dominated by antelope brush, one in
rabbitbrush, and 30 in sagebrush.
Brewer’s Sparrows prefer moderate density sagebrush. In the Kobau/Kilpoola/Chopaka area, 48% nested
in sagebrush of moderate density, 32% in sparse, and 20% in dense (Sarell and McGuinness 1996).
Occurrence is positively correlated to sagebrush density up to 20% cover (Dobler 1990), but bird density
would likely decrease in very dense (>50%) stands (Sarell and McGuinness 1996, Dobler 1990, Harvey
1992).
Brewer’s Sparrows prefer lush sagebrush areas, often occurring at moister, higher elevation sites.
Although presence/absence of Brewer’s Sparrows is correlated to sagebrush density, relative abundance
appears to be correlated with these forb-rich sagebrush habitats (Paczek 2002). Paczek (2002) found a
positive association with large perennials including lupine and parsnip-flowered buckwheat, which was
also noted by Hobbs (2001).
Bird density is inversely related to annual grass cover (Dobler 1990), with between 10% and 40% bare
ground preferred (Harvey 1992). In shrub-steppe habitats they probably benefit from the initial increases
in woody vegetation due to grazing, but are harmed by heavy grazing that removes understory vegetation
(Bock et al. 1992). Harvey (1992) found that bird density decreased with increased grazing.
Warm aspects are primarily used for nesting (Bent 1968, Harvey 1992, BC Environment 1997). The
number of birds increased with increasing slope from 0 to 20%, and decreased at slopes >20% (Harvey
1992).
Nests are typically built in sagebrush, usually near the ground, with a mean height of 30 to 49 cm
(Canning et al. 1987, Campbell et al. 2001). However, birds will nest in giant ryegrass in traditional
areas where sagebrush has been removed or burned off (D. Cannings pers. comm.). Mahony (2001) also
noted Brewer’s Sparrows nesting in a large variety of plants at a site where most of the sagebrush had
been removed by wildfire.
2/17/2016
Page 2 of 6
BREWER’S SPARROW
General Living
Food
Brewer's Sparrow forage for seeds and insects on the ground or on shrub foliage. During the nesting
season they are primarily insectivorous, including in their diet a wide range of arthropods, especially
caterpillars (Gebauer 2002).
As well as the sagebrush breeding habitats, aspen gullies and shrubby wetlands appear to be important
insect foraging areas during the nesting season. After the breeding season, adults and fledged young
were noted to move to aspen gullies or areas with tall deciduous shrubs (Yu 2001). Young aspen (3-6m
tall) with deadfalls and relatively dense understory seem to be preferred over mature aspen habitats (Yu
2001). Two cases of post-fledging use of Douglas-fir stands were also noted (Yu 2001).
Ratings
This model employs a 4-class rating scheme because there is insufficient knowledge of habitat
requirements to use a 6-Class scheme yet there is sufficient knowledge to go beyond a 2-class rating
scheme. This complies with the recommended rating scheme in the RIC standards manual (1999).
Provincial Benchmark
Ecosection
SOB, OKR
Biogeoclimatic Zones
BG, PP, IDF
Habitats
Sagebrush grassland with nearby shrubby riparian
Map Themes
Habitat Use
Life
Requisite
Season
Rating
Code
Ecosystem Attributes
Reproducing
Security/
Thermal
Spring
RE
 sagebrush
Living
Food
Growing
season
LIG
 aspen gullies and shrubby wetlands
Ratings Assumptions
Reproducing – Security/Thermal (RE)
Site Series
 Sagebrush habitats rated up to High if forb understory, up to Moderate if dry
grass understory *
Structural Stage  Stage 3 up to High, others Nil
Shrub Density
 > 50% rated down 1
Range Condition  Mesic (e.g. Poa) seral associations down 1 (from H), dry (e.g. cheatgrass) seral
associations also down 1 (from M) *
Aspect
 Warm aspects rated up to High, cool up to Moderate
Slope
 Gentle to Moderate slopes rated up to High, steep up to Moderate
2/17/2016
Page 3 of 6
BREWER’S SPARROW
General Living during growing season– Food (LIG)
Site Series
 Aspen gullies and shrubby wetlands rated up to High
Structural Stage  Stages 5 to 7 for aspen rated down 1
Range Condition  Poor rated down 1
* In the study area, mesic sagebrush sites (forb understory) are altered by grazing pressure to Kentucky
bluegrass, needlegrass and cheatgrass seral associations, while dry sites (bunchgrass understory) are
generally altered to cheatgrass seral associations.
Map Interpretation
The model for Brewer’s Sparrow predicts suitability for two maps themes: nesting (RE) and general
living during the growing season (LIG), which includes foraging, particularly during the post-fledging
period. The nesting theme overlays the foraging theme on the map.
Both themes are rated using the highest value method, which portrays the rating for the highest suitability
habitat occurring in the polygon.
Nesting habitats that are in close proximity to displayed high value foraging habitats (not covered by
nesting values - i.e. deciduous woodlands and shrubby wetlands), are more likely to be used.
Literature Cited
BC Environment. 1996. Managing Identified Wildlife Guidebook 1.0, Kamloops Forest Region.
Ministry of Environment, Lands and Parks and Ministry of Forests. Internal Government
Review Draft.
BC Environment. 1997. Species and Plant Community Accounts for Identified Wildlife. Ministry of
Environment, Lands and Parks and Ministry of Forests. Internal Government Review Draft.
Bent, A.C. 1968. Life Histories of North American Cardinals, Grosbeaks, Buntings, Towhees, Finches,
Sparrows, and Allies. Part 2. U.S. Natl. Mus. Bull. 237: 1209-1217.
Bock, C.E., V.A. Saab, T.D. Rich and D.S. Dobkin. 1992. Effects of livestock grazing on neotropical
migratory landbirds in western North America. In Status and Management of Neotropical
Migratory Birds. USDA, Forest Service, Rocky Mountain Forest and Range Experiment
Station, Colorado. Gen.Tech.Rep. RM-229.
Bryan, A. and L. Mulholland. 1992. Draft. Species Notes and Management Options for Fifty-four
Wildlife Species of Management Concern in the South Okanagan. Ministry of Environment,
Lands and Parks, Penticton, B.C.
Cannings, R.A., R.J. Cannings and S.G. Cannings. 1987. Birds of the Okanagan Valley, British
Columbia. Royal British Columbia Museum.
Dobler, F.C. 1990. Shrub Steppe Ecosystem Studies. Phase One Completion Report. Nongame
Research Washington Department of Wildlife.
2/17/2016
Page 4 of 6
BREWER’S SPARROW
Gebauer, M. 2002. Sagebrush Brewer’s Sparrow (Spizella breweri breweri). In Standards for Managing
Identified Wildlife, Version 2. K. Paige ed. Min. of Water. Land and Air Protection. Victoria,
BC.
Harvey, D.H. 1992. The Distribution, Density and Habitat of Brewer’s Sparrows Spizella breweri in the
South Okanagan Valley of British Columbia. Ministry of Environment Lands and Parks.
Hlady, D.A. 1990. South Okanagan Conservation Strategy. Ministry of Environment Lands and Parks,
Victoria, B.C.
Krannitz, P.G. and C. Rohner. 2000. Habitat use and distribution of listed neotropical migrant songbirds
in northeastern British Columbia. Pgs. 823-829 in L.M. Darling, ed. Proc. of a Conf. on the
Biology and Management of Species at Risk. Wildl. Br., Min. Environ., Lands and Parks and
Univ. College of the Cariboo. February 1999, Kamloops, BC
Mahony, N.A. 2001. Reproductive ecology and population viability of Brewer’s Sparrows at the
northern edge of their range. Ph.D. Thesis, Univ. of BC.
Mahony, N.A., W.M. Vander Haegen, B.L. Walker and P.G. Krannitz. 2002. Male incubation and
multiple brooding in Brewer’s Sparrows. Wilson Bulletin 103: 441-444.
McAdoo, J.K., W.S. Longland and R.A. Evans. 1989. Nongame bird community responses to sagebrush
invasion of crested wheatgrass seedings. J. Wildl. Manage. 53(2): 494-502.
Paczek, S. 2002. Effects of fine-scale and landscape-level habitat features on sagebrush breeding birds
of the southern Okanagan and Similkameen Valleys, British Columbia. MSc. Thesis, Univ. of
BC.
Royal
British Columbia Museum.
1996.
Endangered
http://rbcm1.rbcm.gov.bc.ca/End_Species/index_es.html
Species
Web
Site.
Address:
Sarell, M.J. and McGuinness, K.P. 1996. Status of the Brewer’s Sparrow in British Columbia.
Ministry of Environment Lands and Parks, Victoria, B.C.
Stevens, V. 1995. Database for wildlife diversity in British Columbia: distribution and habitat use of
amphibians, reptiles, birds and mammals in biogeoclimatic zones. Res. Br., B.C. Min. For.,
Hab. Protect. Br., B.C. Environment, Victoria, B.C. Work. Paper 05/1995.
Terres, J.K. 1995. The Audubon Society Encyclopedia of North American Birds. Wings Books,
Avenel, New Jersey.
Welstead, K. 2002. Factors affecting nest predation of artificial and real Sagebrush Brewer’s Sparrows
(Spizella breweri breweri) nests in the south Okanagan and Similkameen Valleys, British
Columbia. MSc. Thesis, Univ. of BC.
Willing, R.M. 1970. The role of song in the behaviour and evolution of three species of spizellid
sparrow: sonograph and field play-back studies. MSc. Thesis, Simon Fraser University.
Yu, J.H.Y. 2001. Postfledging habitat use and movements of Brewer’s Sparrows (Spizella breweri
breweri) in the South Okanagan Region. MSc. Thesis, Univ. of BC.
2/17/2016
Page 5 of 6
Brewer’s Sparrow Suitability Map