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

Warbling Vireo In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionForest birds

Warbling Vireo in Boreal Hardwood Transition has fallen sharply: down 74% on the route-weighted index since 1968.

-74%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 →
104Routes 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 declinecomputed 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 →

Warbling Vireo has fallen sharply in Boreal Hardwood Transition: down 74% on the route-weighted index since 1968.

Warbling Vireo In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Warbling Vireo in Boreal Hardwood Transition is projected to fall about 55% by 2029 — from 0.48 in 2024 to a central estimate of 0.22 (95% range 0.00–0.74). A 5-year backtest shows a typical error of ±24.4%, with 100% of held-out values landing inside the 95% band.

-55%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 →
0.22Projected 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 →
0.00–0.7495% 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 →
±24.4%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, Warbling Vireo in Boreal Hardwood Transition is projected to fall about 55% by 2029 — from 0.48 in 2024 to a central estimate of 0.22 (95% range 0.00–0.74). A 5-year backtest shows a typical error of ±24.4%, with 100% 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 →
20250.340.000.86
20260.310.000.83
20270.280.000.81
20280.250.000.78
20290.220.000.74

Routes In Boreal Hardwood Transition

Routes recording Warbling Vireo 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 →
GreenbushMINNESOTA122024
Pleasant ValMICHIGAN71997
CathroMICHIGAN72016
HerronMICHIGAN72016
Eagle RiverWISCONSIN72010
TahquamenonMICHIGAN62005
WausaukeeWISCONSIN62010
Bear LakeMICHIGAN52024
Hubbard LakeMICHIGAN51996
RiggsvilleMICHIGAN42019
HarriettaMICHIGAN42019
Walloon Lake 2MICHIGAN42024
MayfieldMICHIGAN42022
Cass LakeMINNESOTA41995
BashawWISCONSIN42022
Walloon LakeMICHIGAN32004
FloodwoodMINNESOTA32012
BenaMINNESOTA31967
BemidjiMINNESOTA31980
WaskishMINNESOTA31982
Tamarac NwrMINNESOTA32002
ShanagoldenWISCONSIN31986
Gibbs CityMICHIGAN22013
MuskallongeMICHIGAN21977
Lake CityMICHIGAN22022

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