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

Brown-headed Cowbird Population Trend in Alabama

All statesGeneralists

Brown-headed Cowbird in Alabama has edged up: up 15% on the route-weighted index since 1968.

+15%Since 1968TrendPercent 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 →
108Routes 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 →
59YearsYears 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 AlabamaNotable 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 Alabama. See the full index history below.

Brown-headed Cowbird Population Forecast in Alabama

If the recent trend holds, Brown-headed Cowbird in Alabama is projected to fall about 35% by 2030 — from 11 in 2025 to a central estimate of 7.2 (95% range 4.2–10). A 5-year backtest shows a typical error of ±22.8%, with 80% of held-out values landing inside the 95% band.

-35%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 →
7.2Projected 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 →
4.2–1095% 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 →
±22.8%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 Alabama is projected to fall about 35% by 2030 — from 11 in 2025 to a central estimate of 7.2 (95% range 4.2–10). A 5-year backtest shows a typical error of ±22.8%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20267.34.310
20277.34.310
20287.24.310
20297.24.210
20307.24.210

Brown-headed Cowbird Survey Routes in Alabama

Routes recording Brown-headed Cowbird in Alabama.
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 →
Elberta5120221986
Howard4620251966
Stevenson3820241996
Calebee2920251993
Rock Chapel2520241995
Jena2320251981
Carrollton2320251993
Autaugaville2220251996
Helicon2220251996
Newton2120241966
Wedgeworth2120251979
Epes2020241980
Mt Olive1920251966
Greensboro1820251966
Wheeler Dam1820251993
Wallsboro1620251966
Valhermoso Spgs1520101966
Billingsley1520251966
Mentone1520231993
Holt1520251993
Valhermoso Spg 21520142014
Eufaula1520241996
Pine Grove1420251966
Alabama Pt1420031966
Blocton1420251969

Brown-headed Cowbird Population Trend in Other States

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

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