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Species · Tennessee · BBS 2025 Release · 1966–2024

Black-throated Blue Warbler Population Trend in Tennessee

All statesForest birds

Black-throated Blue Warbler in Tennessee has surged: up 705% on the route-weighted index since 1968.

+705%Since 1968TrendPercent 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 →
5Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-throated Blue 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 →

Black-throated Blue Warbler has surged in Tennessee: up 705% on the route-weighted index since 1968.

Black-throated Blue Warbler Population Forecast in Tennessee

If the recent trend holds, Black-throated Blue Warbler in Tennessee is projected to fall about 26% by 2029 — from 1.3 in 2024 to a central estimate of 0.98 (95% range 0.58–1.4). A 5-year backtest shows a typical error of ±22.6%, with 60% of held-out values landing inside the 95% band.

-26%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 →
0.98Projected 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 →
0.58–1.495% 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 →
±22.6%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, Black-throated Blue Warbler in Tennessee is projected to fall about 26% by 2029 — from 1.3 in 2024 to a central estimate of 0.98 (95% range 0.58–1.4). A 5-year backtest shows a typical error of ±22.6%, with 60% of held-out values landing inside the 95% band.19662029
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 →
20250.920.511.3
20260.930.531.3
20270.950.541.4
20280.960.561.4
20290.980.581.4

Black-throated Blue Warbler Survey Routes in Tennessee

Routes recording Black-throated Blue 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 →
Newfound Gap2220241990
Mcfarland919861986
Tellico520241995
Cades Cove220241989
Fish Springs220231966

Black-throated Blue Warbler Population Trend in Other States

connecticutgeorgiamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinapennsylvaniarhode-islandvermontvirginiawest-virginiawisconsin

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