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

Brown-headed Cowbird Population Trend in North Dakota

All statesGeneralists

Brown-headed Cowbird in North Dakota has surged: up 84% on the route-weighted index since 1969.

+84%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-headed Cowbird 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 →

long arc increasecomputed 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-headed Cowbird has surged in North Dakota: up 84% on the route-weighted index since 1969.

Brown-headed Cowbird Population Forecast in North Dakota

If the recent trend holds, Brown-headed Cowbird in North Dakota is projected to rise about 12% by 2030 — from 90 in 2025 to a central estimate of 101 (95% range 68–133). A 5-year backtest shows a typical error of ±17.3%, with 100% of held-out values landing inside the 95% band.

+12%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 →
101Projected 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 →
68–13395% 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 →
±17.3%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-headed Cowbird in North Dakota is projected to rise about 12% by 2030 — from 90 in 2025 to a central estimate of 101 (95% range 68–133). A 5-year backtest shows a typical error of ±17.3%, 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 →
20269865130
20279866131
20289967132
202910067132
203010168133

Brown-headed Cowbird Survey Routes in North Dakota

Routes recording Brown-headed Cowbird 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 →
Glen Ullin22720251982
Horsehead Lk20320251980
Bentley16720241988
Sheyenne Lk16420251980
Ft Yates16220041968
Buchanan14120251967
Douglas Crk14020251982
Denbigh12520251968
Gorham11620251968
Dickinson10820251968
Regan10720251968
Edgeley10120251980
Loraine9620191982
Cedar Creek9020221968
Solen9020252005
Cooperstown8620251969
Zap7720241967
Parshall7520131982
Wild Rose7420251982
Danzig 27420252019
Dunn Center7320251968
Bowman7320251967
Golva7220251979
Sydney7119831967
Carpio6920231967

Brown-headed Cowbird Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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