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

Yellow Warbler In Coastal California

All regionsCoastal CaliforniaForest birds

Yellow Warbler in Coastal California has edged up: up 14% on the route-weighted index since 1970.

+14%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 →
85Routes 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 →

No notable trend signals for Yellow Warbler in Coastal California. See the full index history below.

Forecast

If the recent trend holds, Yellow Warbler in Coastal California is projected to fall about 28% by 2029 — from 1.1 in 2024 to a central estimate of 0.77 (95% range 0.13–1.4). A 5-year backtest shows a typical error of ±17%, with 100% of held-out values landing inside the 95% band.

-28%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 →
0.77Projected 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 →
0.13–1.495% 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%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, Yellow Warbler in Coastal California is projected to fall about 28% by 2029 — from 1.1 in 2024 to a central estimate of 0.77 (95% range 0.13–1.4). A 5-year backtest shows a typical error of ±17%, 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 →
20250.800.171.4
20260.790.161.4
20270.790.151.4
20280.780.141.4
20290.770.131.4

Routes In Coastal California

Routes recording Yellow Warbler 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 →
Jofegan 2CALIFORNIA172024
Santa YnezCALIFORNIA112019
CohassetCALIFORNIA112021
San YsidroCALIFORNIA92019
Mesa GrandeCALIFORNIA92024
Sawmill MtnCALIFORNIA62022
Tres PinosCALIFORNIA51982
Foster ParkCALIFORNIA51994
White RiverCALIFORNIA51992
JacksonCALIFORNIA51984
Harbor Lake 2CALIFORNIA52024
Cp. PendletonCALIFORNIA42003
Elizabeth LkCALIFORNIA42016
Lake CachumaCALIFORNIA42016
PenningtonCALIFORNIA31980
FolsomCALIFORNIA32014
SangerCALIFORNIA32024
Green ValleyCALIFORNIA32023
GlennCALIFORNIA32006
Gold HillCALIFORNIA32022
LockwoodCALIFORNIA32024
OnealsCALIFORNIA32009
Angelus OaksCALIFORNIA32017
South LakeCALIFORNIA32006
Red BluffCALIFORNIA22022

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