Spizella breweri 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Emberizidae

Scientific Name: Spizella breweri
Species Authority: Cassin, 1856
Common Name(s):
English Brewer's Sparrow
Taxonomic Notes: Spizella breweri and S. taverneri (Sibley and Monroe 1990, 1993) have been lumped into S. breweri following AOU (1998).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Butchart, S., Harding, M., Bird, J., Mahood, S.
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Previously published Red List assessments:
2009 Least Concern (LC)
2008 Least Concern (LC)
2007 Near Threatened (NT)
2004 Not Recognized (NR)
2000 Not Recognized (NR)
1994 Not Recognized (NR)
1988 Not Recognized (NR)

Geographic Range [top]

Range Description: This species is found in the USA and Canada. The nominate subspecies breweri occurs in the arid intermountain west of the USA (stretching north into south-east Alberta and south-west Saskatchewan, Canada) (Rotenberry 1999, Byers et al. 1995). Further north it is replaced by the subspecies S. b. taverneri (Rotenberry 1999, Byers et al. 1995), which occurs into south-eastern Alaska.
Countries occurrence:
Canada; Mexico; United States
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 134000
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Upper elevation limit (metres): 2000
Range Map: Click here to open the map viewer and explore range.

Population [top]

Current Population Trend: Decreasing
Additional data:
Number of mature individuals: 16000000 Continuing decline of mature individuals: Unknown
Extreme fluctuations: No Population severely fragmented: No
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Habitat and Ecology: This species breeds on sagebrush flats and other open scrubby areas. It winters from just south of the breeding range in south-western USA to central Mexico (Rotenberry 1999, Byers et al. 1995), though the wintering grounds of S.b. taverneri remain largely unknown.
Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Yes
Generation Length (years): 3.8
Movement patterns: Full Migrant

Threats [top]

Major Threat(s): Habitat loss has accelerated owing to the invasion of exotic plants, particularly cheatgrass Bromus tectorum, which has increased fire frequency and altered post-fire successional pathways (Rotenberry 1998).

Citation: BirdLife International. 2012. Spizella breweri. The IUCN Red List of Threatened Species 2012: e.T22734705A40057909. . Downloaded on 29 November 2015.
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