BirdAnalyst
Species · Idaho · BBS 2025 Release · 1966–2024

Willow Flycatcher Population Trend in Idaho

All statesAerial insectivores

Willow Flycatcher in Idaho has surged: up 112% on the route-weighted index since 1971.

+112%Since 1971TrendPercent 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 →
53Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Willow Flycatcher Trends in IdahoNotable 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 →

Willow Flycatcher has surged in Idaho: up 112% on the route-weighted index since 1971.

Willow Flycatcher Population Forecast in Idaho

If the recent trend holds, Willow Flycatcher in Idaho is projected to stay roughly flat through 2029, near 2.2 (95% range 0.39–4.0). A 5-year backtest shows a typical error of ±26.8%, with 100% of held-out values landing inside the 95% band.

-1%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 →
2.2Projected 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 →
0.39–4.095% 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 →
±26.8%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 Idaho is projected to stay roughly flat through 2029, near 2.2 (95% range 0.39–4.0). A 5-year backtest shows a typical error of ±26.8%, 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 →
20252.20.404.0
20262.20.404.0
20272.20.404.0
20282.20.394.0
20292.20.394.0

Willow Flycatcher Survey Routes in Idaho

Routes recording Willow Flycatcher in Idaho.
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 →
Cabarton2420231985
Naples1620241973
Pierce1520071990
Joel1220241989
Cascade1119841971
Cape Horn820241987
Marble Creek820231988
Rochat Divde820231993
Nezperce Nf719991992
Gifford620171971
Grangeville519861986
Golden520161987
Challis520241975
N Fork Cda R520191994
Alturas519861968
Mivoden420231977
Burgdorf420161988
Nezperce320121992
Lolo Pass320191997
Baker320241974
Sawtooth City 2320232015
Cobalt320241991
Deep Creek219851985
Leadore220241974
Dubois220241974

Willow Flycatcher Population Trend in Other States

alaskaarizonaarkansascaliforniacoloradoconnecticutdelawaregeorgiaillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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