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

Brown-headed Cowbird Population Trend in Louisiana

All statesGeneralists

Brown-headed Cowbird in Louisiana has increased: up 26% on the route-weighted index since 1969.

+26%Since 1969TrendPercent 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 →
100Routes 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 LouisianaNotable 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 Louisiana. See the full index history below.

Brown-headed Cowbird Population Forecast in Louisiana

If the recent trend holds, Brown-headed Cowbird in Louisiana is projected to fall about 18% by 2030 — from 17 in 2025 to a central estimate of 14 (95% range 7.4–20). A 5-year backtest shows a typical error of ±24.1%, with 100% of held-out values landing inside the 95% band.

-18%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 →
14Projected 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 →
7.4–2095% 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 →
±24.1%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 Louisiana is projected to fall about 18% by 2030 — from 17 in 2025 to a central estimate of 14 (95% range 7.4–20). A 5-year backtest shows a typical error of ±24.1%, with 100% of held-out values landing inside the 95% band.19672030
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 →
2026147.420
2027147.420
2028147.420
2029147.420
2030147.420

Brown-headed Cowbird Survey Routes in Louisiana

Routes recording Brown-headed Cowbird in Louisiana.
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 →
Woodlawn15920212008
Ramah15320251988
Forked Island 26420112010
Carlisle4819881987
Atchafalaya4120251989
Shaw3520241967
Frogmore3320251998
Ltl Chenier 23220112010
Transylvania3020251998
Port Allen3020242000
Sabine Nwr2820021989
Kraemer2720251997
Rayville 22420252009
River Road2420251987
Hargis2320112005
Forked Island2320252008
Morgan City2320222011
Creole2219871967
Trout2020251988
Derry1919891967
Evelyn1920242004
Lake Cove1920182009
Keystone1820131967
Mayflower1820251967
Ivan1720131998

Brown-headed Cowbird Population Trend in Other States

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

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