BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Ash-throated Flycatcher In Sierra Nevada

All regionsSierra NevadaAerial insectivores

Ash-throated Flycatcher in Sierra Nevada has collapsed: down 76% on the route-weighted index since 1970.

-76%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 →
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 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 collapsed in Sierra Nevada: down 76% 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 33% by 2029 — from 1.0 in 2024 to a central estimate of 0.67 (95% range 0.00–3.1). A 5-year backtest shows a typical error of ±57.2%, with 100% of held-out values landing inside the 95% band.

-33%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 →
0.67Projected 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 →
0.00–3.195% 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 →
±57.2%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 Sierra Nevada is projected to fall about 33% by 2029 — from 1.0 in 2024 to a central estimate of 0.67 (95% range 0.00–3.1). A 5-year backtest shows a typical error of ±57.2%, 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 →
20250.870.003.3
20260.820.003.2
20270.770.003.2
20280.720.003.1
20290.670.003.1

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
Greenhorn MtCALIFORNIA72008
Kings CanyonCALIFORNIA62024
WawonaCALIFORNIA62024
Higgins CornCALIFORNIA52024
CoultervilleCALIFORNIA32019
LakeshoreCALIFORNIA22024
Cottage SpgsCALIFORNIA11975
LumberyardCALIFORNIA12017
Tuolumne GroveCALIFORNIA12018
GeneseeCALIFORNIA11975
DownievilleCALIFORNIA11985
Hat CreekCALIFORNIA11993
PaxtonCALIFORNIA12018
Forest HillCALIFORNIA12004
PlacervilleCALIFORNIA12022
Pine MountainCALIFORNIA12017

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