BirdAnalyst
Species · Idaho · BBS 2026 Release · 1966–2025

Brown-headed Cowbird Population Trend in Idaho

All statesGeneralists

Brown-headed Cowbird in Idaho has edged down: down 16% on the route-weighted index since 1970.

-16%Since 1970TrendPercent 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 →
64Routes 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 IdahoNotable 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-headed Cowbird in Idaho. See the full index history below.

Brown-headed Cowbird Population Forecast in Idaho

If the recent trend holds, Brown-headed Cowbird in Idaho is projected to stay roughly flat through 2030, near 5.6 (95% range 0.00–11). A 5-year backtest shows a typical error of ±57.6%, with 100% of held-out values landing inside the 95% band.

-7%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 →
5.6Projected 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 →
0.00–1195% 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 →
±57.6%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 Idaho is projected to stay roughly flat through 2030, near 5.6 (95% range 0.00–11). A 5-year backtest shows a typical error of ±57.6%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20265.70.0011
20275.70.0011
20285.60.0011
20295.60.0011
20305.60.0011

Brown-headed Cowbird Survey Routes in Idaho

Routes recording Brown-headed Cowbird in Idaho.
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 →
Cascade5519841968
Picabo2820251988
Glenns Ferry2719861968
Ririe2420251971
Mud Lake2120251988
Daniels Res2120251988
Pocatello1820191979
Carey1820251989
Cedar Hill1820241989
Joel1720241989
Naples1420251973
Gifford1420171971
Magic Mtn1420251988
Dubois1120251972
Triangle1020251985
Cabarton1020241985
Pierce820071990
Cape Horn720251972
Challis620251984
Centerville620251972
Acequia620121979
Almo620251988
Baker520241976
Coolin520251986
Twin Buttes420251985

Brown-headed Cowbird Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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