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

Brown-headed Cowbird Population Trend in Georgia

All statesGeneralists

Brown-headed Cowbird in Georgia has surged: up 272% on the route-weighted index since 1968.

+272%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 →
111Routes 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 GeorgiaNotable 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 Georgia: up 272% on the route-weighted index since 1968.

Brown-headed Cowbird Population Forecast in Georgia

If the recent trend holds, Brown-headed Cowbird in Georgia is projected to stay roughly flat through 2030, near 9.3 (95% range 7.1–12). A 5-year backtest shows a typical error of ±9.3%, 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 →
9.3Projected 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 →
7.1–1295% 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 →
±9.3%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 Georgia is projected to stay roughly flat through 2030, near 9.3 (95% range 7.1–12). A 5-year backtest shows a typical error of ±9.3%, with 100% 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 →
20269.06.711
20279.16.811
20289.26.911
20299.27.011
20309.37.112

Brown-headed Cowbird Survey Routes in Georgia

Routes recording Brown-headed Cowbird in Georgia.
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 →
Shiloh5320252012
Newton4820251976
Finleyson2520251976
Cotton2320251972
Henderson2220251973
Fitzgerald2120251976
Stockbridge2020251975
Philema1920252010
Irwinton1920252016
Davis Crossroads1920252011
Macon1820251979
Deepstep1820231975
Lincolnton 21720252018
Weber1720252013
Kite Lake1720252015
Crest1620251973
Ousley1620252015
Hawkinsville1420241966
Rutledge1320251975
Workmore1320251978
Whitesburg1320251992
Good Hope1320252005
Rentz1220251977
Pineora1220231994
Union1220242011

Brown-headed Cowbird Population Trend in Other States

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

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