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Species · Alabama · BBS 2026 Release · 1966–2025

Swainson's Warbler Population Trend in Alabama

All statesForest birds

Swainson's Warbler in Alabama has surged: up 32× on the route-weighted index since 1970.

32×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 →
77Routes 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 →
57YearsYears 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 AlabamaNotable 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 Alabama. See the full index history below.

Swainson's Warbler Population Forecast in Alabama

If the recent trend holds, Swainson's Warbler in Alabama is projected to fall about 55% by 2030 — from 2.2 in 2025 to a central estimate of 0.96 (95% range 0.49–1.4). A 5-year backtest shows a typical error of ±39.1%, with 20% of held-out values landing inside the 95% band.

-55%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 →
0.96Projected 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 →
0.49–1.495% 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 →
±39.1%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 Alabama is projected to fall about 55% by 2030 — from 2.2 in 2025 to a central estimate of 0.96 (95% range 0.49–1.4). A 5-year backtest shows a typical error of ±39.1%, with 20% of held-out values landing inside the 95% band.19682030
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 →
20260.890.421.4
20270.910.441.4
20280.930.461.4
20290.940.471.4
20300.960.491.4

Swainson's Warbler Survey Routes in Alabama

Routes recording Swainson's Warbler in Alabama.
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 →
Sprott-Cahaba Riv3420141999
Greensboro2120251970
Gainestown Ferry1720151999
Carrollton1120251994
Jena820251981
Blocton620251970
Wedgeworth520251985
Holt520252000
Kymulga520252007
Helicon520251996
Millerville420252010
Linden420232019
Warrior Std420252000
Newton420242018
Greensport320251970
Howard320251982
Billingsley320251972
Brundidge320212008
Elamville320251985
Brooksville320252022
Liberty City 2320252017
Vernon320222004
Autaugaville320251996
Chacaloochee Bay320192011
Drummond320222018

Swainson's Warbler Population Trend in Other States

arkansasfloridageorgiakentuckylouisianamarylandmississippinorth-carolinaoklahomasouth-carolinatennesseetexasvirginiawest-virginia

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