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

Red-winged Blackbird Population Trend in California

All statesGeneralists

Red-winged Blackbird in California has held roughly steady: down 5% on the route-weighted index since 1970.

-5%Since 1970TrendPercent 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 →
214Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Red-winged Blackbird Trends in CaliforniaNotable 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 Red-winged Blackbird in California. See the full index history below.

Red-winged Blackbird Population Forecast in California

If the recent trend holds, Red-winged Blackbird in California is projected to rise about 34% by 2029 — from 31 in 2024 to a central estimate of 42 (95% range 2.0–82). A 5-year backtest shows a typical error of ±24.7%, with 100% of held-out values landing inside the 95% band.

+34%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 →
42Projected 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 →
2.0–8295% 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 →
±24.7%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, Red-winged Blackbird in California is projected to rise about 34% by 2029 — from 31 in 2024 to a central estimate of 42 (95% range 2.0–82). A 5-year backtest shows a typical error of ±24.7%, with 100% of held-out values landing inside the 95% band.19682029
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 →
2025454.985
2026444.284
2027443.484
2028432.783
2029422.082

Red-winged Blackbird Survey Routes in California

Routes recording Red-winged Blackbird in California.
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 →
Dorris195220191972
Brawley144320121971
Glenn77820231971
Palo Verde59520241973
Imperial Dam36320101973
Niland36120241973
Athlone35620071973
Atwater34320121972
Buena Vista30320191990
Tres Pinos26620031968
Collegeville 226520232007
Alamo River21520181973
Zamora17420241972
Paxton17420241998
Likely15820241971
Staten Is.15420241994
Jofegan15220232006
Hollister14620111973
Livermore14619911972
Ora Loma12720241972
Redding11919831972
Iron Gate11420191988
Collegeville10020041968
Cedarville10020241974
Tranquillity9620241972

Red-winged Blackbird Population Trend in Other States

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

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