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Species · Tennessee · BBS 2025 Release · 1966–2024

Swainson's Warbler Population Trend in Tennessee

All statesForest birds

Swainson's Warbler in Tennessee has surged: up 24× on the route-weighted index since 1972.

24×Since 1972TrendPercent 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 →
43YearsYears 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 TennesseeNotable 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 →

Swainson's Warbler has surged in Tennessee: up 24× on the route-weighted index since 1972.

Swainson's Warbler Population Forecast in Tennessee

If the recent trend holds, Swainson's Warbler in Tennessee is projected to fall about 41% by 2029 — from 0.59 in 2024 to a central estimate of 0.35 (95% range 0.11–0.59). A 5-year backtest shows a typical error of ±59.6%, with 0% of held-out values landing inside the 95% band.

-41%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 →
0.35Projected 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 →
0.11–0.5995% 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 →
±59.6%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, Swainson's Warbler in Tennessee is projected to fall about 41% by 2029 — from 0.59 in 2024 to a central estimate of 0.35 (95% range 0.11–0.59). A 5-year backtest shows a typical error of ±59.6%, with 0% of held-out values landing inside the 95% band.19672029
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 →
20250.320.080.56
20260.330.090.56
20270.330.090.57
20280.340.100.58
20290.350.110.59

Swainson's Warbler Survey Routes in Tennessee

Routes recording Swainson's Warbler in Tennessee.
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 →
Tellico620241995
Smokey Jct420221978
Willis Sprng420231994
Mcfarland319761972
Mansfield220242009
Silerton220241992
Fish Springs220221998
Cornpone220242024
Elk Valley220221975
Tiptonville120131992
Oliver Spgs120182006
Mecca120231999
Whiteville120221967
Harbuck120232023
Humboldt120241970
Cades Cove120192019

Swainson's Warbler Population Trend in Other States

alabamaarkansasfloridageorgiakentuckylouisianamarylandmississippinorth-carolinaoklahomasouth-carolinatexasvirginiawest-virginia

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