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

Brown-headed Cowbird Population Trend in Florida

All statesGeneralists

Brown-headed Cowbird in Florida has surged: up 207% on the route-weighted index since 1968.

+207%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 →
104Routes 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 FloridaNotable 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 Florida: up 206% on the route-weighted index since 1968.

Brown-headed Cowbird Population Forecast in Florida

If the recent trend holds, Brown-headed Cowbird in Florida is projected to rise about 248% by 2029 — from 1.4 in 2024 to a central estimate of 4.9 (95% range 0.54–9.2). A 5-year backtest shows a typical error of ±316.7%, with 0% of held-out values landing inside the 95% band.

+248%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 →
4.9Projected 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 →
0.54–9.295% 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 →
±316.7%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 Florida is projected to rise about 248% by 2029 — from 1.4 in 2024 to a central estimate of 4.9 (95% range 0.54–9.2). A 5-year backtest shows a typical error of ±316.7%, with 0% 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 →
20254.70.329.0
20264.70.379.1
20274.80.439.1
20284.80.489.2
20294.90.549.2

Brown-headed Cowbird Survey Routes in Florida

Routes recording Brown-headed Cowbird in Florida.
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 →
Lovedale3720111987
Shawano 22120112010
Citrus Park1220241991
Pinetta1020241987
Alligator Pt1020241987
Blackwater820241990
Dowling Park720231987
Flemington719991987
Hildreth 2620242010
Punta Gorda520142014
Miccosukee420231970
Port St Joe420141967
Steinhatchee420221971
Belmont420241980
Sanderson420211985
Hildreth420091987
Kissimmee420031987
Ft Waltn Bch320111966
Mossy Head320111966
Broad Branch320241967
Telogia319851968
Micanopy319911986
Romeo320241980
St Augustine320241982
Sunniland Gr320211997

Brown-headed Cowbird Population Trend in Other States

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

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