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

Bay-breasted Warbler In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionForest birds

Bay-breasted Warbler in Boreal Hardwood Transition has edged down: down 14% on the route-weighted index since 1976.

-14%Since 1976TrendPercent 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 →
30Routes 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 →
38YearsYears 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 Bay-breasted Warbler in Boreal Hardwood Transition. See the full index history below.

Bay-breasted Warbler In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Bay-breasted Warbler in Boreal Hardwood Transition is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±40.8%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.04Projected 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 →
0.00–0.0895% 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 →
±40.8%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, Bay-breasted Warbler in Boreal Hardwood Transition is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±40.8%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.040.000.08
20260.040.000.08
20270.040.000.08
20280.040.000.08
20290.040.000.08

Routes In Boreal Hardwood Transition

Routes recording Bay-breasted 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 →
BerglandMICHIGAN32022
Seney NwrMICHIGAN32011
WaskishMINNESOTA31982
Gibbs CityMICHIGAN21994
CunardMICHIGAN22019
Walloon LakeMICHIGAN21980
CohassetMINNESOTA22012
Crane LakeMINNESOTA22024
MareniscoMICHIGAN12017
BootjackMICHIGAN11995
Ned LakeMICHIGAN12022
HermanMICHIGAN12022
Brocky LakeMICHIGAN11981
ShingletonMICHIGAN11988
CreightonMICHIGAN11980
TahquamenonMICHIGAN12013
GilchristMICHIGAN12003
PickfordMICHIGAN12024
Isabella 2MICHIGAN12018
LockportMINNESOTA12011
Sawbill LndgMINNESOTA12021
Hart LakeMINNESOTA11991
Sawbill CampMINNESOTA12021
JordanMINNESOTA12021
BabbittMINNESOTA12021

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