BirdAnalyst
Species · BCR 18 · BBS 2025 Release · 1966–2024

Sage Thrasher In Shortgrass Prairie

All regionsShortgrass PrairieGeneralists

Sage Thrasher in Shortgrass Prairie has fallen sharply: down 74% on the route-weighted index since 1982.

-74%Since 1982TrendPercent 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 →
16Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
21YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 declinecomputed 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 fallen sharply in Shortgrass Prairie: down 74% on the route-weighted index since 1982.

Forecast

If the recent trend holds, Sage Thrasher in Shortgrass Prairie is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±92.6%, with 80% of held-out values landing inside the 95% band.

n/aChange by 2029TrendPercent 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 →
0.00Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0395% 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 →
±92.6%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 in Shortgrass Prairie is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±92.6%, with 80% of held-out values landing inside the 95% band.19692029
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 →
20250.010.000.04
20260.010.000.04
20270.000.000.04
20280.000.000.04
20290.000.000.03

Routes In Shortgrass Prairie

Routes recording Sage Thrasher in Shortgrass Prairie.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
AbarrCOLORADO21969
Mica ButteCOLORADO21982
CrowleyCOLORADO22017
HaswellCOLORADO22006
GilpinCOLORADO12017
EdisonCOLORADO12021
VillegreenCOLORADO12004
Kiowa 2COLORADO12024
NunnCOLORADO12014
EllicottCOLORADO12024
TimpasCOLORADO12015
RockportCOLORADO12016
Arsenal 2COLORADO12022
Murray LakeNEBRASKA12015
FarleyNEW-MEXICO12011
CheyenneWYOMING11995

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.