BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Allen's Hummingbird In Coastal California

All regionsCoastal CaliforniaGeneralists

Allen's Hummingbird in Coastal California has surged: up 351% on the route-weighted index since 1970.

+351%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 →
39Routes In RegionSurvey 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 SignalsNotable 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 →

Allen's Hummingbird has surged in Coastal California: up 351% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Allen's Hummingbird in Coastal California is projected to rise about 25% by 2029 — from 0.85 in 2024 to a central estimate of 1.1 (95% range 0.50–1.6). A 5-year backtest shows a typical error of ±20.6%, with 100% of held-out values landing inside the 95% band.

+25%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 →
1.1Projected 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 →
0.50–1.695% 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 →
±20.6%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 Coastal California is projected to rise about 25% by 2029 — from 0.85 in 2024 to a central estimate of 1.1 (95% range 0.50–1.6). A 5-year backtest shows a typical error of ±20.6%, 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 →
20251.00.451.6
20261.00.461.6
20271.00.481.6
20281.10.491.6
20291.10.501.6

Routes In Coastal California

Routes recording Allen's Hummingbird in Coastal 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 2CALIFORNIA332024
Elsinore MtnCALIFORNIA112022
ColmaCALIFORNIA61972
Santa Cruz ICALIFORNIA61988
Waterman GapCALIFORNIA42024
S CatalinaCALIFORNIA32022
JofeganCALIFORNIA32009
Santa YnezCALIFORNIA22014
MorenoCALIFORNIA22022
Morro BayCALIFORNIA22005
Mt BaldyCALIFORNIA22023
Lake CachumaCALIFORNIA22003
Glen Ellen 2CALIFORNIA22013
PescaderoCALIFORNIA22024
CalpellaCALIFORNIA11984
CollegevilleCALIFORNIA11973
Tres PinosCALIFORNIA11972
ParkfieldCALIFORNIA11968
Foster ParkCALIFORNIA11992
Harbor LakeCALIFORNIA11991
Oak GroveCALIFORNIA11978
CoalingaCALIFORNIA11985
Point ReyesCALIFORNIA12022
FairfaxCALIFORNIA12019
Sawmill MtnCALIFORNIA12013

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