occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Breeding
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: BREEDING: southern British Columbia, central Idaho, and south-central Montana south through the Great Basin to eastern California, northeastern Arizona, and west-central and northern New Mexico (AOU 1983, Reynolds et al. 1999). Breeds at least irregularly in southern Alberta and southern Saskatchewan (Cannings 1992). NON-BREEDING: central California, southern Nevada, central Arizona, central New Mexico, and central Texas south to southern Baja California, northern Sonora, Chihuahua, Durango, Guanajuato, northern Nuevo Leon, and northern Tamaulipas (AOU 1983, Reynolds et al. 1999).
Length: 22 cm
Weight: 46 grams
Habitat and Ecology
Comments: BREEDING: Sagebrush plains, primarily in arid or semi-arid situations, rarely around towns (AOU 1998). Usually breeds between 1300 and 2000 meters above sea level (Reynolds and Rich 1978). In eastern Washington, showed strongest correlation to amount of sagebrush cover of all shrub-steppe birds; most abundant where sagebrush percent cover was 11% which is similar to estimated historic sagebrush cover (Dobler 1992, Dobler et al. 1996). In northern Great Basin, breeds and forages in tall sagebrush/bunchgrass, juniper/sagebrush/bunchgrass, mountain mahogany/shrub, and aspen/sagebrush/bunchgrass communities (Maser et al. 1984).
Positively correlated with shrub cover, shrub height, bare ground, and horizontal heterogeneity (patchiness); negatively correlated with spiny hopsage, budsage, and grass cover (Rotenberry and Wiens 1980, Wiens and Rotenberry 1981). In Idaho, more likely to occur in sites with higher sagebrush cover and greater spatial similarity within 1-kilometer radius (Knick and Rotenberry 1995). In Nevada, found most often on plots with taller, more dense sagebrush (Medin 1992).
Usually nests within 1 meter of ground in fork of shrub (almost always sagebrush); sometimes nests on ground (Harrison 1978, Reynolds 1981, Rich 1980). In southeastern Idaho, nested in clumps of tall big sagebrush, with dense foliage overhead, invariably a depth of 0.5 meter from nest to shrub crown, and nests tending to be on the southeast side of the shrub (Petersen and Best 1991). Reynolds (1981) recorded mean nest shrub height 89 centimeter, mean nest height 18 centimeter, and mean distance between nest and shrub crown 58 centimeter. For nests placed within shrubs, Rich (1980) observed mean nest shrub height 83 centimeters, mean nest height 23 centimeters, and mean distance between nest and shrub crown 60 centimeters (n = 114 nests). Distance between nest and shrub crown nearly always the same (58 to 60 centimeters) whether nest placed on ground or within shrub, presumably for optimum shading and shelter (Reynolds 1981, Rich 1980).
NONBREEDING: In winter, uses arid and semi-arid scrub, brush and thickets.
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.
Departs from northern breeding areas by end of September, returns in April, May, or June.
Comments: Feeds on a wide variety of insects, including grasshoppers, beetles, weevils, ants, bees, etc. Also feeds on fruits and berries.
Based on studies in:
USA: Arizona, Sonora Desert (Desert or dune)
This list may not be complete but is based on published studies.
Known prey organisms
Based on studies in:
USA: Arizona, Sonora Desert (Desert or dune)
This list may not be complete but is based on published studies.
Density rarely exceeds 30 per square kilometer (Rotenberry and Wiens 1989). In eastern Washington sagebrush shrub-steppe, mean densities reported at 0.09 to 0.2 individuals per hectare (Dobler et al 1996). Breeding density 0.05 individuals per hectare or less in shadscale habitat in eastern Nevada (Medin 1990). Territory size in eastern Idaho averaged 8 territories per 1.86 hectares in one year, 11 territories per 1.14 hectares the following (Reynolds 1981).
Relative abundance significantly positively correlated with the following species in western U.S., based on North American Breeding Bird Survey data (T.D. Rich, unpubl. data): Brewer's Sparrow (SPIZELLA BREWERI; r = 0.87, P < 0.001), Sage Sparrow (AMPHISPIZA BELLI; r = 0.73, P < 0.001), Gray Flycatcher (EMPIDONAX WRIGHTII; r = 0.73, P P < 0.001), Sage Grouse (CENTROCERCUS UROPHASIANUS; r = 0.71, P < 0.001), Rock Wren (SALPINCTES OBSOLETUS; r = 0.61, P < 0.001), Vesper Sparrow (POOECETES GRAMINEUS; r = 0.53, P < 0.001), Prairie Falcon (FALCO MEXICANUS; r = 0.53, P < 0.001), and Green-tailed Towhee (PIPILO CHLORURUS; r = 0.51, P < 0.001).
Life History and Behavior
Clutch size four to seven (usually three to five). Incubation about 15 days, by both sexes. Nestlings altricial and downy. Nestling period about 13 days. Probably can raise two broods per season, but probably only one brood per year in British Columbia (Cannings 1992). In Oregon, reproductive parameters were not associated with climatic variation (Rotenberry and Wiens 1989).
Molecular Biology and Genetics
Barcode data: Oreoscoptes montanus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Oreoscoptes montanus
Public Records: 6
Specimens with Barcodes: 7
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N1B - Critically Imperiled
Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Comments: Range management practices such as mowing, burning, herbicide treatments, and residential and agricultural development have reduced the quantity and quality of sagebrush habitat (Braun et al. 1976, Cannings 1992, Reynolds 1999). HABITAT LOSS, FRAGMENTATION: Removal of sagebrush and conversion to other land uses is detrimental (Castrale 1982). Large scale reduction and fragmentation of sagebrush habitats is occurring in many areas due to land conversion to tilled agriculture, urban and suburban development, and road and power-line rights of way. Range improvement programs remove sagebrush (particularly once grazed sagebrush becomes overly dense) by burning, herbicide application, and mechanical treatment, replacing sagebrush with annual grassland to promote forage for livestock. Burning can result in longer-lasting sagebrush control than chaining (Castrale 1982). GRAZING: Grazing can increase sagebrush density, positively affecting thrasher abundance. Dense stands of sagebrush, however, are considered degraded range for livestock and may be treated to reduce or remove sagebrush. Grazing may also encourage the invasion of non-native grasses, which escalates the fire cycle and converts shrublands to annual grasslands. West (1988, 1996) estimates less than 1% of sagebrush steppe habitats remain untouched by livestock; 20% is lightly grazed, 30% moderately grazed with native understory remaining, and 30% heavily grazed with understory replaced by invasive annuals. The effects of grazing in sagebrush habitats are complex, and depend on intensity, season, duration and extent of alteration to native vegetation. INVASIVE GRASSES: Cheatgrass readily invades disturbed sites, and has come to dominate the grass-forb community of more than half the sagebrush region in the West, replacing native bunchgrasses (Rich 1996). Cheatgrass can create a more continuous grass understory than native bunchgrasses. Dense cheatgrass cover can possibly affect foraging ability for ground foragers, and more readily carries fire than native bunchgrasses. Crested wheatgrass and other non-native annuals have also altered the grass-forb community in many areas of sagebrush shrub-steppe. FIRE: Cheatgrass has altered the natural fire regime on millions of acres in the western range, increasing the frequency, intensity, and size of range fires. Fire kills sagebrush and where non-native grasses dominate, the landscape can be converted to annual grassland as the fire cycle escalates (Paige and Ritter 1998). PREDATION: Are preyed upon by loggerhead shrikes (LANIUS LUDOVICIANUS); predation can be a major factor in breeding success of sagebrush birds (Reynolds 1979). BROOD PARASITISM: Coexists with brown-headed cowbirds (MOLOTHRUS ATER) at various points throughout range; observed to reject cowbird eggs by ejecting eggs from nest (Rich and Rothstein 1985).
Restoration Potential: There is a high probability of sustaining thrashers wherever native sagebrush habitats are maintained with high shrub vigor, tall shrubs, horizontal shrub patchiness, and an open understory of bare ground and native bunchgrasses and forbs. However, sagebrush habitats can be very difficult to restore once invaded by cheatgrass and other noxious non-natives, leading to an escalation of fire frequency and fire intensity that permanently converts shrub-steppe to annual grassland. There are no simple prescriptions for eliminating cheatgrass, medusahead, and other noxious weeds. Restoration of native vegetation at severely degraded sites may be expensive and require long-term dedication that includes continuous weed control, control of disturbances, and repeated reseeding of sagebrush and native understory plants (see Paige and Ritter 1998).
Preserve Selection and Design Considerations: In Idaho, Knick and Rotenberry (1995) found the probability of occupancy increased with increasing homogeneity of the surrounding habitat within a 1-kilometer radius, and with greater percent sagebrush cover. Also, positively correlated with shrub patch size, and negatively correlated with disturbance.
Management Requirements: Will thrive where sagebrush habitat is maintained, with shrubs occurring in tall, clumped, and vigorous stands. Prefers tall shrubs for nesting or song perches and low percent grass cover to facilitate foraging on ground.
SAGEBRUSH CONTROL: Sensitive to sagebrush control; abundance declines with the loss of shrubs. In Wyoming, abundances lower on 22-year old herbicide-treated site (shrub cover approximately 15 percent) than on untreated site (shrub cover > 35 percent), and was not present on 9-year old burned site (shrub cover < 10 percent) (Kerley and Anderson 1995). Castrale (1982) found thrashers persisting in sagebrush islands with tall shrubs within a burned site (10.2 percent shrub cover in islands; max height = 59.0 centimeters), but found no territories within the burn itself (0.0 percent shrub cover), or within plowed (11.8 percent shrub cover; max height = 44.8 centimeters) or chained (5.8 percent shrub cover; max height = 41.4 centimeters) sites reseeded with grasses. In southern Oregon, densities declined following herbicidal spraying and removal of sagebrush and reseeding with crested wheatgrass, where sagebrush cover decreased from 19-24 percent to 4-12 percent (Wiens and Rotenberry 1985). In Idaho, crested wheatgrass seedings did not support sage thrashers (Reynolds and Trost 1980).
FIRE: Fire that kills and completely removes sagebrush cover over large areas would be detrimental. In Idaho, densities remained stable over three years following a prescribed burn that left 50 percent of the sagebrush in a mosaic pattern of burned and unburned sage (sagebrush cover was reduced from an average 21 percent to an average 12 percent) (Petersen and Best 1987).
GRAZING: Not likely affected where livestock grazing regime maintains native vegetation composition and densities. Reported responses to grazing are generally positive, particularly where grazing increases sagebrush cover. In Nevada, positive response to heavy grazing reported in greasewood and Nevada bluegrass habitats (Page et al. 1978, cited in Saab et al. 1995). Reynolds (1980, cited in Saab et al. 1995) reported a positive response to moderate grazing in big sage. In Idaho, Reynolds and Trost (1980) found more nests in sheep-grazed sagebrush with denser cover (14 nests; sage cover = 25 percent) than in ungrazed sagebrush (8 nests; sage cover = 17 percent). Nest success was slightly higher on a site grazed by sheep in spring (big sagebrush cover = 25 percent) than on an ungrazed site (big sagebrush cover = 22.5 percent; Reynolds and Rich 1978).
GRASS COVER: Abundance is negatively correlated with grass cover (Rotenberry and Wiens 1980). Not present in crested wheatgrass plantings (Reynolds and Trost 1980). Primarily a ground forager, foraging success may be reduced by continuous cover of crested wheatgrass, cheatgrass or other non-native grasses (Paige and Ritter 1998).
PESTICIDES: In southern Idaho shrub-steppe, aerial application of Malathion (applied at 585 grams per hectare ultra-low volume, in single-day applications in each of two successive years) reduced food base; nestling foot length was smaller on treated site although there were no observable direct effects on nestling survival (Howe et al. 1996).
Management Research Needs: Understanding of minimum patch sizes, fragmentation effects, spatial juxtaposition of habitat patches and other aspects of landscape ecology needed. Study of the effects of grazing and impact of predation in relation to habitat changes would be useful. Further study of direct and indirect impacts of herbicides and pesticides typically used in sagebrush shrub-steppe rangelands needed. Study of factors that may be differentially affecting sagebrush bird populations might shed light on why sage thrashers appear stable while Brewer's sparrows are widely decreasing (e.g., brood parasitism, effects on wintering grounds, productivity).
Biological Research Needs: Many aspects of biology and ecology are still unknown. Study of migration and wintering ecology and habitat relations needed. Further details needed on site fidelity, territory size, interspecific interactions, juvenile dispersal, diet and metabolism, social behavior in relation to breeding or wintering, life span and survivorship, and response to climatic changes on breeding or wintering sites.
Relevance to Humans and Ecosystems
Stewardship Overview: Appears to be stable or increasing in much of range. Can likely persist with moderate grazing and other land management activities that maintain sagebrush cover, tall vigorous shrubs, and the quality and integrity of native vegetation. Vulnerable where sagebrush habitats are severely degraded or converted to annual grasslands or to other land uses. Sagebrush habitats may be very difficult to restore where non-native grasses and other invasive weeds are pervasive, leading to an escalation of fire cycles that permanently convert sagebrush habitats to annual grassland.
Species Impact: May be beneficial. Reportedly can help control Mormon crickets and other grasshoppers (Knowlton and Harmston 1943).
The sage thrasher (Oreoscoptes montanus) is a medium-sized passerine bird from the family Mimidae, which also includes mockingbirds, tremblers, and New World catbirds. It is the only member of the genus Oreoscoptes. This seems less close to the Caribbean thrashers, but rather to the mockingbirds instead (Hunt et al. 2001, Barber et al. 2004).
O. montanus are pale grey-brown on the upperparts and white on the underparts with dark streaks. They have a slim straight relatively short bill, yellow eyes and a long tail, although not as long as that of other thrashers.
As its name suggests, this bird breeds in western North America, from southern Canada to northern Arizona and New Mexico. Its breeding habitat is in areas with dense stands of sagebrush and rarely in other shrubby areas. The female lays 4 or 5 eggs in a twiggy cup nest built in a low bush. Both parents incubate and feed the young birds.
The male bird sings a series of warbled notes to defend his nesting territory.
These birds have declined in some areas where sagebrush has been removed but are still common where suitable habitat remains. The continued decline of sagebrush habitats in western North America is cause for alarm for this and other sagebrush dependent species.
- Barber, Brian R.; Martínez-Gómez, Juan E. & Peterson, A. Townsend (2004): Systematic position of the Socorro mockingbird Mimodes graysoni. J. Avian Biol. 35: 195-198. doi:10.1111/j.0908-8857.2004.03233.x (HTML abstract)
Names and Taxonomy
Comments: Placed in Sturnidae in Sibley and Ahlquist (1984).