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Species · California · BBS 2025 Release · 1966–2024

Bullock's Oriole Population Trend in California

All statesGeneralists

Bullock's Oriole in California has declined: down 44% on the route-weighted index since 1970.

-44%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 →
219Routes 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 Bullock's Oriole 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 Bullock's Oriole in California. See the full index history below.

Bullock's Oriole Population Forecast in California

If the recent trend holds, Bullock's Oriole in California is projected to stay roughly flat through 2029, near 3.0 (95% range 1.2–4.8). A 5-year backtest shows a typical error of ±35.1%, with 100% of held-out values landing inside the 95% band.

+3%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 →
3.0Projected 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 →
1.2–4.895% 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 →
±35.1%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, Bullock's Oriole in California is projected to stay roughly flat through 2029, near 3.0 (95% range 1.2–4.8). A 5-year backtest shows a typical error of ±35.1%, 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 →
20253.21.45.0
20263.21.45.0
20273.11.34.9
20283.01.24.8
20293.01.24.8

Bullock's Oriole Survey Routes in California

Routes recording Bullock's Oriole 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 →
Iron Gate4220191988
White River3319921972
Kernville2820082008
Dorris2620191972
Yokohl Val2519971972
Greenhorn Mt2420081971
Tres Pinos 22320112005
Gold Hill1920241971
Horse Creek1620191970
Nubieber1620181970
Athlone1620071972
Poway1519801973
Ventucopa1520021972
Bartlett Sps1420181972
Gazelle1420211988
Cp. Pendleton1320031970
Adelaida1320241970
Ono1220111984
Carmel Val1220241973
Rumsey1120081969
Auburn1119801969
Fallsvale1119811970
Redding1119831972
Tres Pinos1020031968
Folsom1020241984

Bullock's Oriole Population Trend in Other States

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