BirdAnalyst
Species · BCR 14 · BBS 2025 Release · 1966–2024

Bay-breasted Warbler In Atlantic Northern Forest

All regionsAtlantic Northern ForestForest birds

Bay-breasted Warbler in Atlantic Northern Forest has collapsed: down 82% on the route-weighted index since 1968.

-82%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 →
85Routes 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 →

Bay-breasted Warbler has collapsed in Atlantic Northern Forest: down 82% on the route-weighted index since 1968.

Bay-breasted Warbler In Atlantic Northern Forest Population Forecast

If the recent trend holds, Bay-breasted Warbler in Atlantic Northern Forest is projected to fall about 14% by 2029 — from 0.07 in 2024 to a central estimate of 0.06 (95% range 0.00–0.36). A 5-year backtest shows a typical error of ±57.1%, with 100% of held-out values landing inside the 95% band.

-14%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 →
0.06Projected 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 →
0.00–0.3695% 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 →
±57.1%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, Bay-breasted Warbler in Atlantic Northern Forest is projected to fall about 14% by 2029 — from 0.07 in 2024 to a central estimate of 0.06 (95% range 0.00–0.36). A 5-year backtest shows a typical error of ±57.1%, 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 →
20250.080.000.38
20260.070.000.38
20270.070.000.37
20280.060.000.37
20290.060.000.36

Routes In Atlantic Northern Forest

Routes recording Bay-breasted Warbler in Atlantic Northern Forest.
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 →
Pillsbury PdMAINE81968
Forest StaMAINE62000
NorthfieldMAINE51981
CharlestonMAINE52016
Clayton LakeMAINE52001
HancockMAINE42000
NesowadnehunMAINE42021
ClarksvilleNEW-HAMPSHIRE42007
CooperMAINE32021
Big TwentyMAINE32008
TopsfieldMAINE31992
Big Twenty 2MAINE32009
Mt ChocoruaNEW-HAMPSHIRE31991
StoweVERMONT32024
FreedomMAINE21976
EastbrookMAINE21972
BaxterMAINE21984
WinnMAINE21998
WaiteMAINE21977
St DavidMAINE22004
TelosMAINE22006
Baker LakeMAINE22001
YankeetuladiMAINE22009
Blue Ridge NNEW-YORK21996
SpeculatorNEW-YORK21984

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