BirdAnalyst
Species · BCR 17 · BBS 2026 Release · 1966–2025

Brown Thrasher In Badlands and Prairies

All regionsBadlands and PrairiesForest birds

Brown Thrasher in Badlands and Prairies has declined: down 49% on the route-weighted index since 1969.

-49%Since 1969TrendPercent 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 →
98Routes 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 →
58YearsYears 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 →

No notable trend signals for Brown Thrasher in Badlands and Prairies. See the full index history below.

Brown Thrasher In Badlands and Prairies Population Forecast

If the recent trend holds, Brown Thrasher in Badlands and Prairies is projected to fall about 34% by 2030 — from 1.4 in 2025 to a central estimate of 0.89 (95% range 0.21–1.6). A 5-year backtest shows a typical error of ±25.4%, with 100% of held-out values landing inside the 95% band.

-34%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 →
0.89Projected 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 →
0.21–1.695% 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 →
±25.4%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, Brown Thrasher in Badlands and Prairies is projected to fall about 34% by 2030 — from 1.4 in 2025 to a central estimate of 0.89 (95% range 0.21–1.6). A 5-year backtest shows a typical error of ±25.4%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20260.960.281.6
20270.940.261.6
20280.930.241.6
20290.910.231.6
20300.890.211.6

Routes In Badlands and Prairies

Routes recording Brown Thrasher in Badlands and Prairies.
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 →
RosebudSOUTH-DAKOTA122011
Miles CityMONTANA82025
ChamberlainSOUTH-DAKOTA82011
Hehn DrawMONTANA72025
RevaSOUTH-DAKOTA72025
TobaccoNORTH-DAKOTA62019
Ft ThompsonSOUTH-DAKOTA62011
MaurineSOUTH-DAKOTA62025
ZapNORTH-DAKOTA52024
SolenNORTH-DAKOTA52025
LaplantSOUTH-DAKOTA52011
OttumwaSOUTH-DAKOTA52025
LodgepoleSOUTH-DAKOTA52025
IsabelSOUTH-DAKOTA52013
White RiverSOUTH-DAKOTA52014
WebsterMONTANA42025
BrandenbergMONTANA42025
Roosevelt PkNORTH-DAKOTA42019
Cedar CreekNORTH-DAKOTA42022
CarsonNORTH-DAKOTA42025
PromiseSOUTH-DAKOTA42014
HardingSOUTH-DAKOTA42025
Cedar PassSOUTH-DAKOTA42025
MarcusSOUTH-DAKOTA42014
LacreekSOUTH-DAKOTA42025

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.