BirdAnalyst
Species · BCR 17 · BBS 2025 Release · 1966–2024

Brown Thrasher In Badlands and Prairies

All regionsBadlands and PrairiesGeneralists

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 →
96Routes 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 →
57YearsYears 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.

Forecast

If the recent trend holds, Brown Thrasher in Badlands and Prairies is projected to fall about 11% by 2029 — from 0.99 in 2024 to a central estimate of 0.88 (95% range 0.20–1.6). A 5-year backtest shows a typical error of ±30.8%, with 80% of held-out values landing inside the 95% band.

-11%Change 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 →
0.88Projected 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 →
0.20–1.695% 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 →
±30.8%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 11% by 2029 — from 0.99 in 2024 to a central estimate of 0.88 (95% range 0.20–1.6). A 5-year backtest shows a typical error of ±30.8%, with 80% of held-out values landing inside the 95% band.19672029
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 →
20250.950.271.6
20260.930.251.6
20270.920.231.6
20280.900.221.6
20290.880.201.6

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
SolenNORTH-DAKOTA92024
BadlandsSOUTH-DAKOTA92023
ChamberlainSOUTH-DAKOTA82011
SavageMONTANA62021
TobaccoNORTH-DAKOTA62019
Ft ThompsonSOUTH-DAKOTA62011
Cedar PassSOUTH-DAKOTA62023
Cabin CreekMONTANA52024
ZapNORTH-DAKOTA52024
GolvaNORTH-DAKOTA52023
LaplantSOUTH-DAKOTA52011
RevaSOUTH-DAKOTA52024
IsabelSOUTH-DAKOTA52013
White RiverSOUTH-DAKOTA52014
BowmanNORTH-DAKOTA42024
Roosevelt PkNORTH-DAKOTA42019
Cedar CreekNORTH-DAKOTA42022
WinnerSOUTH-DAKOTA42024
PromiseSOUTH-DAKOTA42014
MaurineSOUTH-DAKOTA42024
LodgepoleSOUTH-DAKOTA42024
MarcusSOUTH-DAKOTA42014
JordanMONTANA32016
LocateMONTANA32022

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