BirdAnalyst
Species · BCR 15 · BBS 2026 Release · 1966–2025

Ash-throated Flycatcher In Sierra Nevada

All regionsSierra NevadaAerial insectivores

Ash-throated Flycatcher in Sierra Nevada has fallen sharply: down 73% on the route-weighted index since 1970.

-73%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 →
19Routes 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 declinecomputed 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 fallen sharply in Sierra Nevada: down 73% on the route-weighted index since 1970.

Ash-throated Flycatcher In Sierra Nevada Population Forecast

If the recent trend holds, Ash-throated Flycatcher in Sierra Nevada is projected to fall about 21% by 2030 — from 0.78 in 2025 to a central estimate of 0.61 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±60.9%, with 100% of held-out values landing inside the 95% band.

-21%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 →
0.61Projected 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 →
0.00–3.095% 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 →
±60.9%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 Sierra Nevada is projected to fall about 21% by 2030 — from 0.78 in 2025 to a central estimate of 0.61 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±60.9%, 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 →
20260.820.003.2
20270.770.003.1
20280.710.003.1
20290.660.003.0
20300.610.003.0

Routes In Sierra Nevada

Routes recording Ash-throated Flycatcher in Sierra Nevada.
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 →
Bass LakeCALIFORNIA292019
Silver CityCALIFORNIA282013
KernvilleCALIFORNIA132008
WawonaCALIFORNIA92025
Greenhorn MtCALIFORNIA72008
Kings CanyonCALIFORNIA62024
Higgins CornCALIFORNIA42025
CoultervilleCALIFORNIA32019
LakeshoreCALIFORNIA22024
Cottage SpgsCALIFORNIA11975
LumberyardCALIFORNIA12017
Tuolumne GroveCALIFORNIA12025
GeneseeCALIFORNIA11975
DownievilleCALIFORNIA11985
Hat CreekCALIFORNIA11993
PaxtonCALIFORNIA12018
Forest HillCALIFORNIA12004
PlacervilleCALIFORNIA12022
Pine MountainCALIFORNIA12017

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