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

Mourning Warbler Population Trend in West Virginia

All statesForest birds

Mourning Warbler in West Virginia has surged: up 229% on the route-weighted index since 1976.

+229%Since 1976TrendPercent 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 →
12Routes 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 →
48YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Mourning Warbler 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 →

Mourning Warbler has surged in West Virginia: up 229% on the route-weighted index since 1976.

Mourning Warbler Population Forecast in West Virginia

If the recent trend holds, Mourning Warbler in West Virginia is projected to stay roughly flat through 2029, near 0.13 (95% range 0.00–0.38). A 5-year backtest shows a typical error of ±61.3%, 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 →
0.13Projected 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 →
0.00–0.3895% 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 →
±61.3%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, Mourning Warbler in West Virginia is projected to stay roughly flat through 2029, near 0.13 (95% range 0.00–0.38). A 5-year backtest shows a typical error of ±61.3%, with 100% of held-out values landing inside the 95% band.19732029
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 →
20250.140.000.39
20260.140.000.39
20270.140.000.39
20280.140.000.39
20290.130.000.38

Mourning Warbler Survey Routes in West Virginia

Routes recording Mourning Warbler 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 →
Wymer320091995
Glady220232008
Bemis220232001
Valley Head220182016
Richwood220241980
Dailey120241973
Glade Run119971988
Bowden120232000
Glade Run 2120242009
Canaan120051980
Three Forks120241996
Green Bank120221977

Mourning Warbler Population Trend in Other States

connecticutillinoisindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-yorknorth-dakotaohiopennsylvaniavermontwisconsin

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