BirdAnalyst
Species · West Virginia · BBS 2025 Release · 1966–2024

Alder Flycatcher Population Trend in West Virginia

All statesAerial insectivores

Alder Flycatcher in West Virginia has surged: up 282% on the route-weighted index since 1980.

+282%Since 1980TrendPercent 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 →
16Routes 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 →
26YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Alder Flycatcher Trends in West VirginiaNotable 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 →

Alder Flycatcher has surged in West Virginia: up 282% on the route-weighted index since 1980.

Alder Flycatcher Population Forecast in West Virginia

If the recent trend holds, Alder Flycatcher in West Virginia is projected to stay roughly flat through 2029, near 0.19 (95% range 0.06–0.32). A 5-year backtest shows a typical error of ±19.7%, with 100% of held-out values landing inside the 95% band.

+0%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 →
0.19Projected 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 →
0.06–0.3295% 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 →
±19.7%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, Alder Flycatcher in West Virginia is projected to stay roughly flat through 2029, near 0.19 (95% range 0.06–0.32). A 5-year backtest shows a typical error of ±19.7%, with 100% of held-out values landing inside the 95% band.19772029
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 →
20250.180.050.30
20260.180.050.31
20270.180.060.31
20280.180.060.31
20290.190.060.32

Alder Flycatcher Survey Routes in West Virginia

Routes recording Alder Flycatcher in West Virginia.
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 →
Glady520242013
Berryburg319881979
Bemis320232015
Denmar219911991
Mo Of Seneca119861986
Slate119801980
Greer120141979
Spencer119861986
Glade Run 2120242018
Bismark120191984
Ruthbelle120131977
Valley Head120242015
Three Forks119861986
Richwood120172006
Green Bank120111994
Sugar Grove119831983

Alder Flycatcher Population Trend in Other States

alaskaconnecticutidahoillinoisindianaiowamainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-dakotavermontvirginiawashingtonwisconsin

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