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Species · BCR 12 · BBS 2025 Release · 1966–2024

Nashville Warbler In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionForest birds

Nashville Warbler in Boreal Hardwood Transition has surged: up 187% on the route-weighted index since 1968.

+187%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 →
124Routes 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 →
58YearsYears 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 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 →

Nashville Warbler has surged in Boreal Hardwood Transition: up 187% on the route-weighted index since 1968.

Nashville Warbler In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Nashville Warbler in Boreal Hardwood Transition is projected to rise about 28% by 2029 — from 16 in 2024 to a central estimate of 21 (95% range 16–26). A 5-year backtest shows a typical error of ±13.8%, with 100% of held-out values landing inside the 95% band.

+28%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 →
21Projected 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 →
16–2695% 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 →
±13.8%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, Nashville Warbler in Boreal Hardwood Transition is projected to rise about 28% by 2029 — from 16 in 2024 to a central estimate of 21 (95% range 16–26). A 5-year backtest shows a typical error of ±13.8%, with 100% 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 →
2025201525
2026201526
2027211526
2028211626
2029211626

Routes In Boreal Hardwood Transition

Routes recording Nashville Warbler in Boreal Hardwood Transition.
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 →
Sherry LakeMINNESOTA1022022
JordanMINNESOTA1002023
Sawbill LndgMINNESOTA722024
Crane LakeMINNESOTA722024
ChisholmMINNESOTA722024
GlendaleMINNESOTA712024
Brocky LakeMICHIGAN702024
LockportMINNESOTA602024
Hart LakeMINNESOTA572024
BlackduckMINNESOTA452022
Little ForkMINNESOTA432024
BabbittMINNESOTA432023
Betchler LksMICHIGAN412024
Sawbill CampMINNESOTA412024
IshpemingMICHIGAN392023
WaskishMINNESOTA352024
Nett LakeMINNESOTA342024
MuskallongeMICHIGAN312024
HovlandMINNESOTA312024
SidnawMICHIGAN302024
OntonagonMICHIGAN292019
Land O' Lakes 2WISCONSIN292024
Red LakeMINNESOTA272024
CreightonMICHIGAN252023
Brush CreekMICHIGAN232016

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