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

Blue-winged Warbler In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionForest birds

Blue-winged Warbler in Boreal Hardwood Transition has edged up: up 13% on the route-weighted index since 1980.

+13%Since 1980TrendPercent 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 →
24Routes 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 →
29YearsYears 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 →

No notable trend signals for Blue-winged Warbler in Boreal Hardwood Transition. See the full index history below.

Blue-winged Warbler In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Blue-winged Warbler in Boreal Hardwood Transition is projected to fall about 46% by 2030 — from 0.07 in 2025 to a central estimate of 0.04 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±54.3%, with 100% of held-out values landing inside the 95% band.

-46%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 →
0.04Projected 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 →
0.00–0.0795% 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 →
±54.3%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, Blue-winged Warbler in Boreal Hardwood Transition is projected to fall about 46% by 2030 — from 0.07 in 2025 to a central estimate of 0.04 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±54.3%, with 100% of held-out values landing inside the 95% band.19732030
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 →
20260.040.000.07
20270.040.000.07
20280.040.000.07
20290.040.000.07
20300.040.000.07

Routes In Boreal Hardwood Transition

Routes recording Blue-winged 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 →
DebsMINNESOTA32017
Weirgor SpringsWISCONSIN32025
Walloon LakeMICHIGAN21980
IrmaWISCONSIN22022
AmbergWISCONSIN22018
MareniscoMICHIGAN12005
CunardMICHIGAN12021
Bear LakeMICHIGAN12025
Lake CityMICHIGAN11974
SkeelsMICHIGAN12011
OberlinMICHIGAN12006
CathroMICHIGAN12011
Sand LakeMICHIGAN12014
HarriettaMICHIGAN12005
BlackduckMINNESOTA12005
Nett LakeMINNESOTA12018
Tamarac NwrMINNESOTA11998
Grand ViewWISCONSIN12011
Union TwpWISCONSIN11992
CouderayWISCONSIN11996
ExelandWISCONSIN12005
HollisterWISCONSIN11973
Washington IWISCONSIN11973
BashawWISCONSIN12025

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