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

Allen's Hummingbird Population Trend in California

All statesGeneralists

Allen's Hummingbird in California has declined: down 27% on the route-weighted index since 1970.

-27%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 →
71Routes 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 Allen's Hummingbird 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 Allen's Hummingbird in California. See the full index history below.

Allen's Hummingbird Population Forecast in California

If the recent trend holds, Allen's Hummingbird in California is projected to stay roughly flat through 2029, near 0.47 (95% range 0.08–0.85). A 5-year backtest shows a typical error of ±20.5%, with 100% of held-out values landing inside the 95% band.

-7%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 →
0.47Projected 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 →
0.08–0.8595% 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 →
±20.5%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, Allen's Hummingbird in California is projected to stay roughly flat through 2029, near 0.47 (95% range 0.08–0.85). A 5-year backtest shows a typical error of ±20.5%, 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 →
20250.480.090.86
20260.470.090.86
20270.470.090.86
20280.470.080.86
20290.470.080.85

Allen's Hummingbird Survey Routes in California

Routes recording Allen's Hummingbird 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 →
Harbor Lake 23320242014
Elsinore Mtn1120222017
Redwood N.P. 2920122012
Crescent Cty720241973
Santa Cruz I619881988
Colma619721969
Lonesome Rdg419961994
Big Flat420142014
Waterman Gap420241975
Rio Dell320111972
Jofegan320092009
S Catalina320221988
Mt Baldy220232014
Holmes220221968
Lake Cachuma220031975
Santa Ynez220141993
Moreno220222022
Glen Ellen 2220132005
Laytonville220171972
Morro Bay220051973
South Fork Mtn220192000
Pescadero220241992
Silver City219761975
Horse Creek119901970
Honeydew120171968

Allen's Hummingbird Population Trend in Other States

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