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

Ash-throated Flycatcher In Coastal California

All regionsCoastal CaliforniaAerial insectivores

Ash-throated Flycatcher in Coastal California has surged: up 88% on the route-weighted index since 1970.

+88%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 →
117Routes 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 →
57YearsYears 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 →

Ash-throated Flycatcher has surged in Coastal California: up 88% on the route-weighted index since 1970.

Ash-throated Flycatcher In Coastal California Population Forecast

If the recent trend holds, Ash-throated Flycatcher in Coastal California is projected to rise about 42% by 2030 — from 12 in 2025 to a central estimate of 17 (95% range 13–22). A 5-year backtest shows a typical error of ±22.2%, with 80% of held-out values landing inside the 95% band.

+42%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 →
17Projected 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 →
13–2295% 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 →
±22.2%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, Ash-throated Flycatcher in Coastal California is projected to rise about 42% by 2030 — from 12 in 2025 to a central estimate of 17 (95% range 13–22). A 5-year backtest shows a typical error of ±22.2%, with 80% of held-out values landing inside the 95% band.19682030
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 →
2026171221
2027171221
2028171321
2029171321
2030171322

Routes In Coastal California

Routes recording Ash-throated Flycatcher 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 →
White RiverCALIFORNIA1261992
RumseyCALIFORNIA672008
Red BluffCALIFORNIA502025
JacksonCALIFORNIA491992
Yokohl ValCALIFORNIA471997
OnealsCALIFORNIA452024
TujungaCALIFORNIA442021
Lake CachumaCALIFORNIA392016
SisquocCALIFORNIA372014
Tres Pinos 2CALIFORNIA362011
Elsinore MtnCALIFORNIA342025
Lake BerryessaCALIFORNIA332025
JacumbaCALIFORNIA322025
Cal Hot SpgsCALIFORNIA322019
Mt Pinos 2CALIFORNIA312024
Yolla BollyCALIFORNIA312025
CopperopolisCALIFORNIA302024
San Benito Mtn.CALIFORNIA292009
Lockwood ValCALIFORNIA272019
Mt BaldyCALIFORNIA272024
FolsomCALIFORNIA262025
LockwoodCALIFORNIA262025
Cuyamaca PkCALIFORNIA252025
Gold HillCALIFORNIA252025
Lake SuccessCALIFORNIA241996

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