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Species · BCR 12 · BBS 2026 Release · 1966–2025

Blackburnian Warbler In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionForest birds

Blackburnian Warbler in Boreal Hardwood Transition has surged: up 183% on the route-weighted index since 1968.

+183%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 →
115Routes 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 →
59YearsYears 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 183% 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 stay roughly flat through 2030, near 3.5 (95% range 2.5–4.5). A 5-year backtest shows a typical error of ±16.1%, with 80% of held-out values landing inside the 95% band.

-1%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 →
3.5Projected 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 →
2.5–4.595% 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 →
±16.1%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 stay roughly flat through 2030, near 3.5 (95% range 2.5–4.5). A 5-year backtest shows a typical error of ±16.1%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20263.32.34.3
20273.32.34.3
20283.42.44.4
20293.42.44.4
20303.52.54.5

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 →
Crane LakeMINNESOTA302025
Sawbill LndgMINNESOTA262025
Sherry LakeMINNESOTA192022
BerglandMICHIGAN162022
Imp LakeMICHIGAN162019
LockportMINNESOTA162025
JordanMINNESOTA162025
Eagle RiverWISCONSIN152025
Sawbill CampMINNESOTA132025
BlackduckMINNESOTA122022
GlendaleMINNESOTA122025
Gibbs CityMICHIGAN112025
Hart LakeMINNESOTA112025
ChisholmMINNESOTA112024
Land O LakesWISCONSIN102016
ShanagoldenWISCONSIN92025
MareniscoMICHIGAN82019
Land O' Lakes 2WISCONSIN72025
HermanMICHIGAN62013
Grand ViewWISCONSIN62025
Popple RiverWISCONSIN62025
CavourWISCONSIN62025
Ned LakeMICHIGAN52025
GilchristMICHIGAN52021
Scott'S MarshMICHIGAN52010

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