BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Willow Flycatcher In Great Basin

All regionsGreat BasinAerial insectivores

Willow Flycatcher in Great Basin has fallen sharply: down 61% on the route-weighted index since 1970.

-61%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 →
118Routes 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 →

Willow Flycatcher has fallen sharply in Great Basin: down 61% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Willow Flycatcher in Great Basin is projected to fall about 47% by 2029 — from 1.1 in 2024 to a central estimate of 0.59 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±46.4%, with 80% of held-out values landing inside the 95% band.

-47%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 →
0.59Projected 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 →
0.00–1.495% 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 →
±46.4%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, Willow Flycatcher in Great Basin is projected to fall about 47% by 2029 — from 1.1 in 2024 to a central estimate of 0.59 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±46.4%, with 80% 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 →
20250.710.001.5
20260.680.001.5
20270.650.001.5
20280.620.001.5
20290.590.001.4

Routes In Great Basin

Routes recording Willow Flycatcher in Great Basin.
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 →
Fish LakeOREGON342024
KendallWASHINGTON252024
IndexWASHINGTON181971
JoelIDAHO122024
JosephOREGON122024
NewhalemWASHINGTON122024
WaitsburgWASHINGTON122004
Turnbull NwrWASHINGTON82023
BlitzenOREGON71972
PendletonOREGON72024
PomeroyWASHINGTON72024
ConcreteWASHINGTON72024
DorrisCALIFORNIA62019
GiffordIDAHO62017
ArdenvoirWASHINGTON61987
Lake ChelanWASHINGTON62024
TonasketWASHINGTON52018
Suiattle RivWASHINGTON52019
ZumwaltOREGON42005
WapatoWASHINGTON42022
LeavenworthWASHINGTON42024
Index 2WASHINGTON42023
Cascade RivWASHINGTON42006
BakerIDAHO32024
BlyOREGON31974

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