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

Ash-throated Flycatcher In Coastal California

All regionsCoastal CaliforniaAerial insectivores

Ash-throated Flycatcher in Coastal California has surged: up 102% on the route-weighted index since 1970.

+102%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 →
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 →

Ash-throated Flycatcher has surged in Coastal California: up 102% 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 20% by 2029 — from 15 in 2024 to a central estimate of 17 (95% range 13–22). A 5-year backtest shows a typical error of ±18.9%, with 100% of held-out values landing inside the 95% band.

+20%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 →
17Projected 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 →
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 →
±18.9%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 20% by 2029 — from 15 in 2024 to a central estimate of 17 (95% range 13–22). A 5-year backtest shows a typical error of ±18.9%, 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 →
2025171321
2026171321
2027171321
2028171322
2029171322

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
JacksonCALIFORNIA491992
Yokohl ValCALIFORNIA471997
OnealsCALIFORNIA452024
Red BluffCALIFORNIA442024
TujungaCALIFORNIA442021
Lake CachumaCALIFORNIA392016
FolsomCALIFORNIA372024
SisquocCALIFORNIA372014
AdelaidaCALIFORNIA362024
Tres Pinos 2CALIFORNIA362011
Yolla BollyCALIFORNIA332024
Lake BerryessaCALIFORNIA322024
Elsinore MtnCALIFORNIA322024
Cal Hot SpgsCALIFORNIA322019
Mt Pinos 2CALIFORNIA312024
Cuyamaca PkCALIFORNIA302024
CopperopolisCALIFORNIA302024
JacumbaCALIFORNIA292024
Gold HillCALIFORNIA292024
San Benito Mtn.CALIFORNIA292009
CohassetCALIFORNIA272024
Lockwood ValCALIFORNIA272019
Mt BaldyCALIFORNIA272024

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