BirdAnalyst
Species · Kentucky · BBS 2025 Release · 1966–2024

Brown-headed Cowbird Population Trend in Kentucky

All statesGeneralists

Brown-headed Cowbird in Kentucky has declined: down 38% on the route-weighted index since 1968.

-38%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 →
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 →
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 KentuckyNotable 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 Kentucky. See the full index history below.

Brown-headed Cowbird Population Forecast in Kentucky

If the recent trend holds, Brown-headed Cowbird in Kentucky is projected to rise about 39% by 2029 — from 8.3 in 2024 to a central estimate of 11 (95% range 6.8–16). A 5-year backtest shows a typical error of ±37%, with 80% of held-out values landing inside the 95% band.

+39%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 →
11Projected 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 →
6.8–1695% 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 →
±37%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 Kentucky is projected to rise about 39% by 2029 — from 8.3 in 2024 to a central estimate of 11 (95% range 6.8–16). A 5-year backtest shows a typical error of ±37%, with 80% 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 →
2025127.116
2026127.016
2027126.916
2028126.916
2029116.816

Brown-headed Cowbird Survey Routes in Kentucky

Routes recording Brown-headed Cowbird in Kentucky.
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 →
Bays Fork4920191999
Staffordsvil4819971996
Paintsville4719951979
Joy3220231966
Million3119861966
Bardwell 22620242006
Iron Bridge1819981966
Morganfield1820242022
Mammoth Cave1820141995
Plum1720241966
Hodgenville1520031971
Kehoe 21420242005
Goshen1419991966
Keysburg1320241968
Pine Ridge1319781966
Eastview1320241967
Daniel Boone1319881966
Buena Vista1320171966
East Union1320221966
Cumberlnd Gp1220181966
Gatewood1220191966
Boxville1219831966
Mammoth Cave North1220132009
Merrimac1120241967
Dixie1120191967

Brown-headed Cowbird Population Trend in Other States

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

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.