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Toxostoma bendirei 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Mimidae

Scientific Name: Toxostoma bendirei
Species Authority: (Coues, 1873)
Common Name(s):
English Bendire's Thrasher
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
Identification information: 25 cm. Small, drab almost uniformly brown thrasher. Similar spp. Told from similar Curve-billed Thrasher T. curvirostre by its smaller size; shorter, straighter bill; paler, yellow iris; small triangular (not round) spots on breast; buffy (not dark) malar; and buff-brown (not grayish) flanks. Voice Slow choppy phrases of semi-musical thrush-like whistles and chattering calls.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2ce+3ce+4ce ver 3.1
Year Published: 2017
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Inigo, E., Rosenberg, K., Wells, J., Beardmore, C. & McCreedy, C.
Facilitator/Compiler(s): Benstead, P., Bird, J., Harding, M., Sharpe, C J
Justification:
This species is listed as Vulnerable because it is suspected to be undergoing a rapid decline. However, recent trends are poorly documented, and further information may warrant a revision of its status. Putative threats are poorly understood, but the species may be negatively impacted by habitat destruction and degradation resulting from agricultural expansion and development, as well as climate change.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Toxostoma bendirei is found in south-west USA and north-west Mexico, from Mojave desert in California east into southern Nevada, southern Utah and south-western Colorado south to central Sonora. Its status in Baja California is unresolved (England and Laudenslayer 1993, Brewer and MacKay 2001). Within this range its distribution is patchy and in some cases poorly known (owing to low observer density in desert regions) (England and Laudenslayer 1993). Individuals in the northern portion of the range migrate east and south in the winter and overlap with more eastern and southern residents (England and Laudenslayer 1993, Brewer and MacKay 2001). The species is now so rare that trends cannot be estimated reliably from Breeding Bird Survey data (J. Wells, K. Rosenberg and E. Inigo in litt. 2003), but declines between 1966 and 2013 equated to a decline of 4.6% per year (Sauer et al. 2014).

Countries occurrence:
Native:
Mexico; United States
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:466000
Continuing decline in extent of occurrence (EOO):UnknownExtreme 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):1600
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The US population is estimated at 90,000 individuals (Rosenberg et al. 2016). 



Trend Justification:  This species has undergone a large and statistically significant decrease over the last 40 years in North America (-90.6% decline over 40 years, equating to a -44.7% decline per decade; data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007). The BBS trend data from 1966-2013 gives a decline of 4.6% per year, with a decline of 4.1% per year between 2003-2013 (Sauer et al. 2014). Additionally, recent half-life analyses from Partners In Flight suggest that the species could undergo a 50% decline over 18 years (Rosenberg et al. 2016). Therefore, the species is likely undergoing a continuing decline in the range of 30-49% over 3 generations (c.12.5 years).
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:It is found in sparse desert habitats from sea level in Sonora to approximately 1,800 m in Utah (England and Laudenslayer 1993, Brewer and MacKay 2001). Throughout its range, breeders favour relatively open grassland, shrubland or woodland with scattered shrubs or trees; it is not found in dense vegetation. It forages primarily on the ground, probing for insects and other arthropods, but will also eat seeds and berries (England and Laudenslayer 1993). It also digs with its bill, but less frequently, not as powerfully nor as efficiently as other thrashers (England and Laudenslayer 1993). In the Mojave desert, California, migration begins as soon as breeding finishes, with breeding grounds vacated by late August (Brewer and MacKay 2001).

Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):4.2
Movement patterns:Full Migrant

Threats [top]

Major Threat(s): Populations have been eliminated by dense urbanisation around Tucson and by large scale agriculture along the Gila River. In California potential threats may include harvesting of Joshua trees and other yuccas, overgrazing and off-road vehicle activity. However, there have been suggestions that clearing and agricultural activities actually favour this species (England and Laudenslayer 1993). Competition with the Curve-billed Thrasher Toxostroma curvirostre for a depleted food supply may have contributed to a decline in the population. Breeding is delayed and potentially less successful as a result of drought conditions (McCreedy and van Ripper III 2015), which may increase in line with climate change, and thus this could be a significant threat into the future. Energy/resource extraction is also listed in Rosenberg et al. (2016) as a potential threat to this species with alternative energy development occurring in the Sonoran desert.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The species has been classified as a "Species of Special Concern" by California Department of Fish and Game, and protected from take. It is classified as a C1 “Species of Greatest Conservation Need” by Arizona Game and Fish Department. No information exists on other management actions (England and Laudenslayer 1993). The species occurs within a number of protected areas. Recently a Desert Thrashers Working Group has been formed to determine what management actions need to be taken (C. Beardmore in litt. 2016).

Conservation Actions Proposed
Research its ecology and determine key habitat requirements. Research the benefits of an increase in scattered junipers from grazing. Study potential competition with Curve-billed Thrashers. Avoid disturbance to and development of important habitats. Determine the taxonomy of Baha Californian populations.

Amended [top]

Amended reason: Edited Geographic Range text and removed a country from the Countries of Occurrence list. Edited Conservation Actions Information text and updated Systematic Monitoring Scheme and whether it occurs in Protected Areas or not. Edited Threats Information text and added new threats to the table. Edited Trend justification text. The reference list was updated, and new Contributors and a new Facilitator/Compiler were added.

Citation: BirdLife International. 2017. Toxostoma bendirei. (amended version published in 2016) The IUCN Red List of Threatened Species 2017: e.T22711108A110276662. . Downloaded on 24 June 2017.
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