BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Sage Thrasher Population Analysis

MimidaeArid-land birdsOreoscoptes montanus

Sage Thrasher has surged: up 154% on the route-weighted index since 1970.

+154%Since 1970TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
554RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Sage Thrasher

The Sage Thrasher (Oreoscoptes montanus) is a North American member of the Mockingbirds & Thrashers (Mimidae). In this analysis it is grouped with the arid-land birds.

Size
8–12 in long (20–30 cm) — a slender, long-tailed songbird (typical for the family)
Habitat
Deserts, dry scrub and brushland of the Southwest.
Diet
Seeds, insects and cactus fruit of arid-land plants.
Range
Recorded on 554 Breeding Bird Survey routes across 14 states, most concentrated in the Great Basin.
Family
Mimidae · Arid-land birds

Notable Sage Thrasher TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Sage Thrasher has surged in surveyed states: up 154% on the route-weighted index since 1970.

Sage Thrasher Population Forecast

If the recent trend holds, Sage Thrasher is projected to rise about 31% by 2030 — from 1.0 in 2025 to a central estimate of 1.4 (95% range 0.70–2.0). A 5-year backtest shows a typical error of ±40%, with 100% of held-out values landing inside the 95% band.

+31%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
1.4Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.70–2.095% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±40%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Sage Thrasher is projected to rise about 31% by 2030 — from 1.0 in 2025 to a central estimate of 1.4 (95% range 0.70–2.0). A 5-year backtest shows a typical error of ±40%, with 100% of held-out values landing inside the 95% band.19682030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20261.30.672.0
20271.30.682.0
20281.30.692.0
20291.40.692.0
20301.40.702.0

Where the Sage Thrasher Is Detected

BBS routes recording Sage Thrasher, sized by most recent count.

Sage Thrasher Population Trend by State

Sage Thrasher population trend by state.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizona-85%197018
California+298%197331
Colorado+735%197068
Idaho+79%197140
Montana-55%197041
Nebraskainsufficient datan/a1
Nevada-49%197046
New Mexico+210%197219
North Dakotainsufficient datan/a1
Oregon+23%197049
South Dakotainsufficient datan/a4
Utah-7%197097
Washington+144%197233
Wyoming+94%1970106

Sage Thrasher Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Sage Thrasher population trend by Bird Conservation Region.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Great Basin-35%1970200
Northern Rockies+115%1970121
Sierra Nevada+219%19825
Southern Rockies / Colorado Plateau+139%1970143
Badlands and Prairies+4%197053
Shortgrass Prairie-74%198216

Sage Thrasher Conservation Status

Our route-weighted index shows it up about 154% since 1970.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.