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Species · Georgia · BBS 2025 Release · 1966–2024

Brown-headed Cowbird Population Trend in Georgia

All statesGeneralists

Brown-headed Cowbird in Georgia has surged: up 238% on the route-weighted index since 1968.

+238%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 →
110Routes 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 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 238% 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 rise about 22% by 2029 — from 7.5 in 2024 to a central estimate of 9.1 (95% range 6.9–11). A 5-year backtest shows a typical error of ±9.3%, with 100% of held-out values landing inside the 95% band.

+22%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 →
9.1Projected 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 →
6.9–1195% 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 →
±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 rise about 22% by 2029 — from 7.5 in 2024 to a central estimate of 9.1 (95% range 6.9–11). A 5-year backtest shows a typical error of ±9.3%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20258.86.611
20268.96.711
20279.06.711
20289.16.811
20299.16.911

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 →
Tazewell4520241969
Wrightsville2120241966
Workmore2120191978
Boston2020241975
Philema1920242010
Davis Crossroads1920212011
Henderson1820241973
Deepstep1820231975
Candler1720242009
Good Hope1520242005
Rock Branch1520242005
Hawkinsville1420241966
Pitts1320241977
Owensboro1320242010
Bowdon1220241973
Stockbridge1220231975
Pineora1220231994
Sunny Side1220192006
Woodstock1220212006
Lincolnton1120171966
Hiram1120181975
Ousley1120242015
Fitzgerald1020241976
Maxeys1020241966
Washington1020241975

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 2026-05-22.