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

Blackburnian Warbler In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionForest birds

Blackburnian Warbler in Boreal Hardwood Transition has surged: up 201% on the route-weighted index since 1968.

+201%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 →
113Routes 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 →

Blackburnian Warbler has surged in Boreal Hardwood Transition: up 201% on the route-weighted index since 1968.

Blackburnian Warbler In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Blackburnian Warbler in Boreal Hardwood Transition is projected to rise about 26% by 2029 — from 2.7 in 2024 to a central estimate of 3.4 (95% range 2.4–4.4). A 5-year backtest shows a typical error of ±17.5%, with 80% 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 →
3.4Projected 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 →
2.4–4.495% 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 →
±17.5%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, Blackburnian Warbler in Boreal Hardwood Transition is projected to rise about 26% by 2029 — from 2.7 in 2024 to a central estimate of 3.4 (95% range 2.4–4.4). A 5-year backtest shows a typical error of ±17.5%, with 80% 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 →
20253.22.24.3
20263.32.34.3
20273.32.34.3
20283.42.44.4
20293.42.44.4

Routes In Boreal Hardwood Transition

Routes recording Blackburnian 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 LakeMINNESOTA192022
BerglandMICHIGAN162022
Imp LakeMICHIGAN162019
LockportMINNESOTA162024
Sawbill LndgMINNESOTA152024
JordanMINNESOTA122023
BlackduckMINNESOTA122022
Sawbill CampMINNESOTA112024
ChisholmMINNESOTA112024
Crane LakeMINNESOTA102024
Land O LakesWISCONSIN102016
Eagle RiverWISCONSIN102024
Hart LakeMINNESOTA92024
CavourWISCONSIN92024
MareniscoMICHIGAN82019
Popple RiverWISCONSIN82024
RacoMICHIGAN72024
HermanMICHIGAN62013
Gibbs CityMICHIGAN62024
Land O' Lakes 2WISCONSIN62024
MellenWISCONSIN62024
Crystal FlsMICHIGAN52024
TahquamenonMICHIGAN52024
GilchristMICHIGAN52021
Scott'S MarshMICHIGAN52010

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