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Species · BCR 4 · BBS 2026 Release · 1966–2025

Tennessee Warbler In BCR 4

All regionsBCR 4Forest birds

Tennessee Warbler in BCR 4 has collapsed: down 76% on the route-weighted index since 1995.

-76%Since 1995TrendPercent 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 RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
19YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 declinecomputed 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 →

Tennessee Warbler has collapsed in BCR 4: down 76% on the route-weighted index since 1995.

Tennessee Warbler In BCR 4 Population Forecast

If the recent trend holds, Tennessee Warbler in BCR 4 is projected to fall about 100% by 2030 — from 0.05 in 2025 to a central estimate of 0.00 (95% range 0.00–0.16). A 5-year backtest shows a typical error of ±244.9%, with 60% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.1695% 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 →
±244.9%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, Tennessee Warbler in BCR 4 is projected to fall about 100% by 2030 — from 0.05 in 2025 to a central estimate of 0.00 (95% range 0.00–0.16). A 5-year backtest shows a typical error of ±244.9%, with 60% 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 →
20260.000.000.16
20270.000.000.16
20280.000.000.16
20290.000.000.16
20300.000.000.16

Routes In BCR 4

Routes recording Tennessee Warbler in BCR 4.
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 →
KuskulanaALASKA22017
EagleALASKA12025
Birch LakeALASKA12017
CantwellALASKA12017
Kenny LakeALASKA11990
SourdoughALASKA11995
ChickenALASKA12025
Donelly DomeALASKA12012
DeltaALASKA12024
Nabesna RoadALASKA12015
Mccarthy Rd2ALASKA12018

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