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Species · Virginia · BBS 2026 Release · 1966–2025

Swainson's Warbler Population Trend in Virginia

All statesForest birds

Swainson's Warbler in Virginia has surged: up 203% on the route-weighted index since 1975.

+203%Since 1975TrendPercent 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 →
11Routes 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 →
46YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Swainson's Warbler Trends in VirginiaNotable 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 Swainson's Warbler in Virginia. See the full index history below.

Swainson's Warbler Population Forecast in Virginia

If the recent trend holds, Swainson's Warbler in Virginia is projected to fall about 23% by 2030 — from 0.19 in 2025 to a central estimate of 0.14 (95% range 0.01–0.28). A 5-year backtest shows a typical error of ±154.5%, with 100% of held-out values landing inside the 95% band.

-23%Change by 2030TrendPercent 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 →
0.14Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.01–0.2895% 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 →
±154.5%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, Swainson's Warbler in Virginia is projected to fall about 23% by 2030 — from 0.19 in 2025 to a central estimate of 0.14 (95% range 0.01–0.28). A 5-year backtest shows a typical error of ±154.5%, with 100% of held-out values landing inside the 95% band.19692030
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 →
20260.140.000.28
20270.140.000.28
20280.140.000.28
20290.140.000.28
20300.140.010.28

Swainson's Warbler Survey Routes in Virginia

Routes recording Swainson's Warbler in 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 →
Pine Mtn.720251996
Dismal Swamp420161992
Newsoms220242012
Saltville119971972
Nat Tunnel120252025
Branchville120161969
Isom120241978
Putnam120252025
Cornland119751975
Iron Mtn.120002000
Iron Mountain 3120212021

Swainson's Warbler Population Trend in Other States

alabamaarkansasfloridageorgiakentuckylouisianamarylandmississippinorth-carolinaoklahomasouth-carolinatennesseetexaswest-virginia

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.