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

Anna's Hummingbird Population Trend in California

All statesGeneralists

Anna's Hummingbird in California has surged: up 145% on the route-weighted index since 1970.

+145%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 →
206Routes 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 Anna'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 →

long arc increasecomputed 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 →

Anna's Hummingbird has surged in California: up 145% on the route-weighted index since 1970.

Anna's Hummingbird Population Forecast in California

If the recent trend holds, Anna's Hummingbird in California is projected to stay roughly flat through 2029, near 2.2 (95% range 1.7–2.7). A 5-year backtest shows a typical error of ±17.4%, with 80% of held-out values landing inside the 95% band.

-9%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 →
2.2Projected 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 →
1.7–2.795% 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 →
±17.4%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, Anna's Hummingbird in California is projected to stay roughly flat through 2029, near 2.2 (95% range 1.7–2.7). A 5-year backtest shows a typical error of ±17.4%, 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 →
20252.11.72.6
20262.21.72.6
20272.21.72.7
20282.21.72.7
20292.21.72.7

Anna's Hummingbird Survey Routes in California

Routes recording Anna'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 →
Elsinore Mtn3920241970
Moreno1920241970
Lake Cachuma1720161972
Fairfax1620241972
San Ysidro1420191973
Green Valley1420231971
Tres Pinos1120031968
Poway1119801973
Coyote1120241972
Waterman Gap1120241973
Tres Pinos 21120112005
Colma1019721968
Rumsey920081970
Morro Bay920191973
Lake Hemet 2920231992
Folsom820241984
Mt Laguna819871970
Mt Baldy820241970
Arvin820191978
Fish Rock720141969
Orange Cove720161977
Pearblossom720191971
Sisquoc720141970
Adelaida720241970
White River719921975

Anna's Hummingbird Population Trend in Other States

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