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

Black-and-white Warbler In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionForest birds

Black-and-white Warbler in Boreal Hardwood Transition has surged: up 351% on the route-weighted index since 1968.

+351%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 →
125Routes 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 →

Black-and-white Warbler has surged in Boreal Hardwood Transition: up 351% on the route-weighted index since 1968.

Black-and-white Warbler In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Black-and-white Warbler in Boreal Hardwood Transition is projected to stay roughly flat through 2029, near 6.5 (95% range 5.4–7.5). A 5-year backtest shows a typical error of ±12.4%, with 40% of held-out values landing inside the 95% band.

-8%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 →
6.5Projected 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 →
5.4–7.595% 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 →
±12.4%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-and-white Warbler in Boreal Hardwood Transition is projected to stay roughly flat through 2029, near 6.5 (95% range 5.4–7.5). A 5-year backtest shows a typical error of ±12.4%, with 40% 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 →
20256.25.17.3
20266.35.27.3
20276.35.37.4
20286.45.37.5
20296.55.47.5

Routes In Boreal Hardwood Transition

Routes recording Black-and-white 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 →
DebsMINNESOTA242024
JordanMINNESOTA232023
BigforkMINNESOTA212024
NebishMINNESOTA212023
ChisholmMINNESOTA202024
Crane LakeMINNESOTA192024
GlendaleMINNESOTA182024
MellenWISCONSIN182024
Sherry LakeMINNESOTA172022
Nett LakeMINNESOTA172024
MahtowaMINNESOTA152023
Little ForkMINNESOTA142024
Tamarac NwrMINNESOTA142024
Weirgor SpringsWISCONSIN142024
TahquamenonMICHIGAN132024
Hart LakeMINNESOTA132024
BlackduckMINNESOTA132022
FlambeauWISCONSIN132024
CavourWISCONSIN132024
Iron RiverWISCONSIN122024
Amnicon FallsWISCONSIN122024
OntonagonMICHIGAN112019
HermanMICHIGAN112022
Crystal FlsMICHIGAN112024
PickfordMICHIGAN112024

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