BirdAnalyst
Species · North Dakota · BBS 2026 Release · 1966–2025

Brown Thrasher Population Trend in North Dakota

All statesForest birds

Brown Thrasher in North Dakota has declined: down 44% on the route-weighted index since 1969.

-44%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 →
51Routes In StateSurvey 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 Brown Thrasher Trends in North DakotaNotable 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 North Dakota. See the full index history below.

Brown Thrasher Population Forecast in North Dakota

If the recent trend holds, Brown Thrasher in North Dakota is projected to stay roughly flat through 2030, near 2.1 (95% range 0.00–4.5). A 5-year backtest shows a typical error of ±27%, with 100% of held-out values landing inside the 95% band.

+5%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 →
2.1Projected 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 →
0.00–4.595% 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 →
±27%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 North Dakota is projected to stay roughly flat through 2030, near 2.1 (95% range 0.00–4.5). A 5-year backtest shows a typical error of ±27%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20262.30.004.7
20272.30.004.7
20282.20.004.6
20292.20.004.6
20302.10.004.5

Brown Thrasher Survey Routes in North Dakota

Routes recording Brown Thrasher in North Dakota.
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 →
Sydney819831967
Edgeley720241980
Tobacco620191968
Walcott520231967
Zap520241967
Solen520252005
Kempton420171967
Emerado420251973
Roosevelt Pk420191982
Cedar Creek420221969
Carson420251988
Danzig 2420252019
Forman320251968
Cooperstown320251970
Dickinson320251969
Dunn Center320251969
Gorham320251968
Golva320251979
Glen Ullin320251982
Sheyenne Lk320251980
Braddock320231988
Danzig220141982
Webster220211989
Rolla220221969
Ft Yates220041968

Brown Thrasher Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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