BirdAnalyst
Species · BCR 23 · BBS 2025 Release · 1966–2024

Brown Thrasher In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionGeneralists

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 →
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 →

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.

Forecast

If the recent trend holds, Brown Thrasher in Prairie Hardwood Transition is projected to fall about 30% by 2029 — from 1.8 in 2024 to a central estimate of 1.3 (95% range 0.25–2.3). A 5-year backtest shows a typical error of ±33.1%, with 80% of held-out values landing inside the 95% band.

-30%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 →
1.3Projected 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 →
0.25–2.395% 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 →
±33.1%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 30% by 2029 — from 1.8 in 2024 to a central estimate of 1.3 (95% range 0.25–2.3). A 5-year backtest shows a typical error of ±33.1%, with 80% of held-out values landing inside the 95% band.19662029
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 →
20251.50.512.6
20261.50.442.5
20271.40.382.4
20281.30.312.4
20291.30.252.3

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 →
Buena VistaWISCONSIN142024
BriggsvilleWISCONSIN102024
N AndoverWISCONSIN82024
WiotaWISCONSIN82024
KnappMINNESOTA72019
Sherburne NrMINNESOTA72024
WhitewaterMINNESOTA62000
CumberlandWISCONSIN62023
HighlandWISCONSIN62024
BeloitWISCONSIN62023
OlaMICHIGAN52024
CohoctahMICHIGAN52023
Brook ParkMINNESOTA52024
Chatfield 2MINNESOTA52024
VickeryOHIO52024
HatfieldWISCONSIN51998
N FreedomWISCONSIN52024
MerideanWISCONSIN52023
GreshamWISCONSIN52024
PackertownINDIANA42004
New BuffaloMICHIGAN42014
PrincetonMINNESOTA42024
Le CenterMINNESOTA42016
Caledonia 2MINNESOTA42024
WeyerhauserWISCONSIN42023

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