BirdAnalyst
Species · BCR 11 · BBS 2025 Release · 1966–2024

Brown Thrasher In Prairie Potholes

All regionsPrairie PotholesGeneralists

Brown Thrasher in Prairie Potholes has fallen sharply: down 57% on the route-weighted index since 1969.

-57%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 →
120Routes 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 →

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 Potholes: down 57% on the route-weighted index since 1969.

Forecast

If the recent trend holds, Brown Thrasher in Prairie Potholes is projected to stay roughly flat through 2029, near 2.0 (95% range 0.07–4.0). A 5-year backtest shows a typical error of ±10.9%, with 100% of held-out values landing inside the 95% band.

+1%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 →
2.0Projected 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 →
0.07–4.095% 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 →
±10.9%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 Potholes is projected to stay roughly flat through 2029, near 2.0 (95% range 0.07–4.0). A 5-year backtest shows a typical error of ±10.9%, with 100% 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 →
20252.30.324.2
20262.20.264.1
20272.10.204.1
20282.10.134.0
20292.00.074.0

Routes In Prairie Potholes

Routes recording Brown Thrasher in Prairie Potholes.
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 →
Wolf PointMONTANA112024
ZearingIOWA81995
MaynardMINNESOTA82015
TracyMINNESOTA82024
Winside 2NEBRASKA82022
SydneyNORTH-DAKOTA81983
WorthingtonMINNESOTA72024
FranklinMINNESOTA72024
LambertMONTANA72024
WinsideNEBRASKA72003
EdgeleyNORTH-DAKOTA72024
ReganNORTH-DAKOTA72022
FairmontMINNESOTA62023
TildenNEBRASKA62024
BrittonSOUTH-DAKOTA62023
CondeSOUTH-DAKOTA61984
GettysburgSOUTH-DAKOTA62023
PantherIOWA52024
TitonkaIOWA52024
ChandlerMINNESOTA52023
Eagle CreekNEBRASKA52024
WalcottNORTH-DAKOTA52023
White LakeSOUTH-DAKOTA52011
GormanSOUTH-DAKOTA52009
BurchinalIOWA42024

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