BirdAnalyst
Species · North Dakota · BBS 2025 Release · 1966–2024

Brown-headed Cowbird Population Trend in North Dakota

All statesGeneralists

Brown-headed Cowbird in North Dakota has surged: up 82% on the route-weighted index since 1969.

+82%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 →
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 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 82% 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 24% by 2029 — from 81 in 2024 to a central estimate of 101 (95% range 68–133). A 5-year backtest shows a typical error of ±19%, with 100% of held-out values landing inside the 95% band.

+24%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 →
101Projected 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 →
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 →
±19%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 24% by 2029 — from 81 in 2024 to a central estimate of 101 (95% range 68–133). A 5-year backtest shows a typical error of ±19%, 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 →
20259865130
20269866131
20279966132
202810067132
202910168133

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 →
Horsehead Lk20920241980
Douglas Crk18220241982
Bentley16720241988
Ft Yates16220041968
Denbigh13620241968
Danzig 213020242019
Sheyenne Lk12220241980
Carson11520241988
Gorham11120181968
Regan10520221968
Edgeley10420241980
Loraine9620191982
Buchanan9220241967
Cedar Creek9020221968
Dickinson8720241968
Solen8320242005
Wimbledon8220241981
Zap7720241967
Parshall7520131982
Wild Rose7220241982
Sydney7119831967
Glen Ullin7120221982
Carpio6920231967
Danzig6520141982
Cooperstown6320241969

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 2026-05-22.