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.

Brown Thrasher In Prairie Potholes Population 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.