BirdAnalyst
Species · BCR 23 · BBS 2026 Release · 1966–2025

Brown Thrasher In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionForest birds

Brown Thrasher in Prairie Hardwood Transition has fallen sharply: down 57% on the route-weighted index since 1968.

-57%Since 1968TrendPercent 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 →
161Routes 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 →
59YearsYears 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 →

Brown Thrasher has fallen sharply in Prairie Hardwood Transition: down 57% on the route-weighted index since 1968.

Brown Thrasher In Prairie Hardwood Transition Population Forecast

If the recent trend holds, Brown Thrasher in Prairie Hardwood Transition is projected to fall about 43% by 2030 — from 2.2 in 2025 to a central estimate of 1.3 (95% range 0.23–2.3). A 5-year backtest shows a typical error of ±30.2%, with 100% of held-out values landing inside the 95% band.

-43%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 →
1.3Projected 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 →
0.23–2.395% 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 →
±30.2%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 Prairie Hardwood Transition is projected to fall about 43% by 2030 — from 2.2 in 2025 to a central estimate of 1.3 (95% range 0.23–2.3). A 5-year backtest shows a typical error of ±30.2%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20261.50.492.5
20271.50.422.5
20281.40.362.4
20291.30.302.4
20301.30.232.3

Routes In Prairie Hardwood Transition

Routes recording Brown Thrasher in Prairie Hardwood Transition.
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 →
Sherburne NrMINNESOTA122025
AnnatonWISCONSIN122025
VickeryOHIO92025
BriggsvilleWISCONSIN82025
TrempealeauWISCONSIN72025
KnoxINDIANA62025
FestinaIOWA62025
WhitewaterMINNESOTA62000
DresserWISCONSIN62025
StratfordWISCONSIN62025
Hazel GreenWISCONSIN62025
WiotaWISCONSIN62025
CoopersvilleMICHIGAN52025
Brook ParkMINNESOTA52024
HatfieldWISCONSIN51998
N AndoverWISCONSIN52025
PackertownINDIANA42004
ScottvilleMICHIGAN42025
New BuffaloMICHIGAN42014
PrincetonMINNESOTA42025
Le CenterMINNESOTA42016
Chatfield 2MINNESOTA42025
WeyerhauserWISCONSIN42025
CochraneWISCONSIN42025
OmroWISCONSIN42001

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