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

Tricolored Blackbird Population Trend in California

All statesGeneralists

Tricolored Blackbird in California has fallen sharply: down 58% on the route-weighted index since 1970.

-58%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 →
89Routes 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 Tricolored 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 →

long arc declinecomputed 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 →

Tricolored Blackbird has fallen sharply in California: down 58% on the route-weighted index since 1970.

Tricolored Blackbird Population Forecast in California

If the recent trend holds, Tricolored Blackbird in California is projected to fall about 10% by 2029 — from 5.6 in 2024 to a central estimate of 5.0 (95% range 0.00–30). A 5-year backtest shows a typical error of ±290.1%, with 100% of held-out values landing inside the 95% band.

-10%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 →
5.0Projected 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 →
0.00–3095% 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 →
±290.1%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, Tricolored Blackbird in California is projected to fall about 10% by 2029 — from 5.6 in 2024 to a central estimate of 5.0 (95% range 0.00–30). A 5-year backtest shows a typical error of ±290.1%, 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 →
20256.10.0031
20265.80.0031
20275.50.0031
20285.30.0030
20295.00.0030

Tricolored Blackbird Survey Routes in California

Routes recording Tricolored 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 →
Oneals529020111983
Riovista32620242010
Atwater23320121971
Dorris21520071972
Jacumba20019991994
Mark West14019921972
Greenfield11320241979
Moreno8620171972
Poloma8619951993
Oroville8020121972
Westley7020231974
Copperopolis7020221979
Gold Hill6519901990
Bakersfield6020191968
Oilfields5619761968
Ventucopa4520021981
Lockwood4520221973
Iron Gate4520111991
Yolla Bolly4320221976
Onyx4219981969
Athlone4120071972
Gazelle4020101988
South Lake4020062006
Redding3819751972
Shafter3719891971

Tricolored Blackbird Population Trend in Other States

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