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

Yellow-headed Blackbird Population Trend in California

All statesGeneralists

Yellow-headed Blackbird in California has declined: down 39% on the route-weighted index since 1970.

-39%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 →
74Routes 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 Yellow-headed 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 Yellow-headed Blackbird in California. See the full index history below.

Yellow-headed Blackbird Population Forecast in California

If the recent trend holds, Yellow-headed Blackbird in California is projected to rise about 245% by 2029 — from 0.49 in 2024 to a central estimate of 1.7 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±168.4%, with 80% of held-out values landing inside the 95% band.

+245%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 →
1.7Projected 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 →
0.00–4.795% 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 →
±168.4%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, Yellow-headed Blackbird in California is projected to rise about 245% by 2029 — from 0.49 in 2024 to a central estimate of 1.7 (95% range 0.00–4.7). A 5-year backtest shows a typical error of ±168.4%, with 80% 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 →
20251.80.004.7
20261.80.004.7
20271.70.004.7
20281.70.004.7
20291.70.004.7

Yellow-headed Blackbird Survey Routes in California

Routes recording Yellow-headed 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 →
Dorris75620191973
Blythe5119791973
Arvin3820151971
Anza 23220052005
Oak Grove2519841984
Onyx2419801972
Ora Loma2119831973
Brawley2020101971
Parker Dam2020071973
Likely1620241971
Palo Verde1320241973
Macdoel1220191976
Yreka1120191975
Elizabeth Lk719861979
Sattley720191972
Benton720231973
Honey Lake620241972
Alamo River619941973
Paxton520102004
Crowley Lake420241972
Westley419961972
Clear Lk Res420161977
Lenwood419791973
Hat Creek420071973
Buena Vista420191991

Yellow-headed Blackbird Population Trend in Other States

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