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Species · California · BBS 2026 Release · 1966–2025

Ash-throated Flycatcher Population Trend in California

All statesAerial insectivores

Ash-throated Flycatcher in California has increased: up 46% on the route-weighted index since 1970.

+46%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 →
219Routes In StateSurvey 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 Ash-throated Flycatcher Trends in CaliforniaNotable 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 Ash-throated Flycatcher in California. See the full index history below.

Ash-throated Flycatcher Population Forecast in California

If the recent trend holds, Ash-throated Flycatcher in California is projected to rise about 30% by 2030 — from 7.0 in 2025 to a central estimate of 9.1 (95% range 6.5–12). A 5-year backtest shows a typical error of ±9.5%, with 100% of held-out values landing inside the 95% band.

+30%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 →
9.1Projected 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 →
6.5–1295% 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 →
±9.5%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 California is projected to rise about 30% by 2030 — from 7.0 in 2025 to a central estimate of 9.1 (95% range 6.5–12). A 5-year backtest shows a typical error of ±9.5%, with 100% 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 →
20268.96.412
20279.06.412
20289.06.412
20299.06.512
20309.16.512

Ash-throated Flycatcher Survey Routes in California

Routes recording Ash-throated Flycatcher in 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 River12619921972
Rumsey6720081969
Red Bluff5020251968
Jackson4919921972
Yokohl Val4719971973
Oneals4520241972
Tujunga4420211970
Glamis4220181968
Lake Cachuma3920161972
Sisquoc3720141970
Tres Pinos 23620112005
Elsinore Mtn3420251970
Lake Berryessa3320252023
Kelso Valley3220251973
Jacumba3220251973
Cal Hot Spgs3220191993
Mt Pinos 23120242005
Yolla Bolly3120251973
Iron Gate3120191988
Copperopolis3020241972
Bass Lake2920191972
San Benito Mtn.2920092003
Silver City2820131974
Lockwood Val2720191970
Mt Baldy2720241970

Ash-throated Flycatcher Population Trend in Other States

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