BirdAnalyst
Species · BCR 32 · BBS 2026 Release · 1966–2025

Wilson's Warbler In Coastal California

All regionsCoastal CaliforniaForest birds

Wilson's Warbler in Coastal California has surged: up 118% on the route-weighted index since 1971.

+118%Since 1971TrendPercent 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 →
77Routes 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 →

Wilson's Warbler has surged in Coastal California: up 118% on the route-weighted index since 1971.

Wilson's Warbler In Coastal California Population Forecast

If the recent trend holds, Wilson's Warbler in Coastal California is projected to rise about 39% by 2030 — from 2.1 in 2025 to a central estimate of 3.0 (95% range 1.8–4.1). A 5-year backtest shows a typical error of ±79.1%, with 20% of held-out values landing inside the 95% band.

+39%Change by 2030TrendPercent 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 →
3.0Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
1.8–4.195% 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 →
±79.1%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, Wilson's Warbler in Coastal California is projected to rise about 39% by 2030 — from 2.1 in 2025 to a central estimate of 3.0 (95% range 1.8–4.1). A 5-year backtest shows a typical error of ±79.1%, with 20% of held-out values landing inside the 95% band.19692030
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 →
20262.81.64.0
20272.91.74.0
20282.91.74.1
20292.91.74.1
20303.01.84.1

Routes In Coastal California

Routes recording Wilson's 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 →
Point ReyesCALIFORNIA342025
Waterman GapCALIFORNIA182025
PescaderoCALIFORNIA172025
Morro BayCALIFORNIA62013
AnzaCALIFORNIA61981
Red BluffCALIFORNIA42025
CalpellaCALIFORNIA41986
FairfaxCALIFORNIA42024
SisquocCALIFORNIA42014
JacksonCALIFORNIA41986
Foster ParkCALIFORNIA31979
FallsvaleCALIFORNIA31975
Green ValleyCALIFORNIA32023
Lake CachumaCALIFORNIA31974
Glen EllenCALIFORNIA32004
CoalingaCALIFORNIA22005
Sawmill MtnCALIFORNIA22014
Elizabeth LkCALIFORNIA22015
CrestonCALIFORNIA21983
ShafterCALIFORNIA21973
Yolla BollyCALIFORNIA22013
Staten Is.CALIFORNIA22013
San Benito Mtn.CALIFORNIA22007
RumseyCALIFORNIA12008
RiovistaCALIFORNIA12005

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.