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

Costa's Hummingbird In Coastal California

All regionsCoastal CaliforniaGeneralists

Costa's Hummingbird in Coastal California has surged: up 75% on the route-weighted index since 1970.

+75%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 →
41Routes 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 →
55YearsYears 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 →

Costa's Hummingbird has risen sharply in Coastal California: up 75% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Costa's Hummingbird in Coastal California is projected to fall about 47% by 2029 — from 0.74 in 2024 to a central estimate of 0.40 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±50.8%, with 100% of held-out values landing inside the 95% band.

-47%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 →
0.40Projected 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 →
0.00–1.095% 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 →
±50.8%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, Costa's Hummingbird in Coastal California is projected to fall about 47% by 2029 — from 0.74 in 2024 to a central estimate of 0.40 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±50.8%, 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 →
20250.410.001.0
20260.400.001.0
20270.400.001.0
20280.400.001.0
20290.400.001.0

Routes In Coastal California

Routes recording Costa'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 →
Elsinore MtnCALIFORNIA192024
Foster ParkCALIFORNIA141993
Angelus OaksCALIFORNIA132005
Oak GroveCALIFORNIA72024
RumseyCALIFORNIA41978
Mt PinosCALIFORNIA41983
MorenoCALIFORNIA42024
JofeganCALIFORNIA42023
Jofegan 2CALIFORNIA42024
Harbor LakeCALIFORNIA31974
VentucopaCALIFORNIA31995
SisquocCALIFORNIA22012
AdelaidaCALIFORNIA21970
AnzaCALIFORNIA21995
Green ValleyCALIFORNIA22023
Elizabeth LkCALIFORNIA21992
Lake Hemet 2CALIFORNIA22016
Santa YnezCALIFORNIA12013
San YsidroCALIFORNIA12004
CoalingaCALIFORNIA12003
PowayCALIFORNIA11979
S CatalinaCALIFORNIA11994
Sawmill MtnCALIFORNIA12013
TujungaCALIFORNIA12018
El ToroCALIFORNIA11987

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