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

Willow Flycatcher Population Trend in Wyoming

All statesAerial insectivores

Willow Flycatcher in Wyoming has declined: down 38% on the route-weighted index since 1970.

-38%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 →
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 →
51YearsYears 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 WyomingNotable 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 Willow Flycatcher in Wyoming. See the full index history below.

Willow Flycatcher Population Forecast in Wyoming

If the recent trend holds, Willow Flycatcher in Wyoming is projected to fall about 42% by 2029 — from 0.42 in 2024 to a central estimate of 0.24 (95% range 0.00–0.91). A 5-year backtest shows a typical error of ±36.6%, with 100% of held-out values landing inside the 95% band.

-42%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 →
0.24Projected 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 →
0.00–0.9195% 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 →
±36.6%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 Wyoming is projected to fall about 42% by 2029 — from 0.42 in 2024 to a central estimate of 0.24 (95% range 0.00–0.91). A 5-year backtest shows a typical error of ±36.6%, 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 →
20250.280.000.94
20260.270.000.93
20270.260.000.92
20280.250.000.92
20290.240.000.91

Willow Flycatcher Survey Routes in Wyoming

Routes recording Willow Flycatcher in Wyoming.
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 →
Wilson1420241980
Moskee1320001989
Dayton1120241980
Buckskin Mtn820211980
Moskee 2420132002
Fontenelle320241982
Alpine320241979
Mayoworth320181997
Green River319821977
Otto220042004
Colter Bay219981968
Redbird219791979
Mammoth220212015
Hunter Peak219931989
Seedskadee220232023
Soda Lake220241981
Boulder220091982
Big Sandy220222005
Fiddler Lk220241990
Ne Entrance120211988
Cody120241997
Basin120231981
Sundance120121978
Dubois120231987
Bill120002000

Willow Flycatcher Population Trend in Other States

alaskaarizonaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsin

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