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Species · BCR 14 · BBS 2026 Release · 1966–2025

Mourning Warbler In Atlantic Northern Forest

All regionsAtlantic Northern ForestForest birds

Mourning Warbler in Atlantic Northern Forest has edged up: up 15% on the route-weighted index since 1968.

+15%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 →
117Routes 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 →

No notable trend signals for Mourning Warbler in Atlantic Northern Forest. See the full index history below.

Mourning Warbler In Atlantic Northern Forest Population Forecast

If the recent trend holds, Mourning Warbler in Atlantic Northern Forest is projected to stay roughly flat through 2030, near 0.55 (95% range 0.12–0.98). A 5-year backtest shows a typical error of ±32%, with 100% of held-out values landing inside the 95% band.

-7%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 →
0.55Projected 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 →
0.12–0.9895% 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 →
±32%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, Mourning Warbler in Atlantic Northern Forest is projected to stay roughly flat through 2030, near 0.55 (95% range 0.12–0.98). A 5-year backtest shows a typical error of ±32%, with 100% 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 →
20260.550.120.99
20270.550.120.98
20280.550.120.98
20290.550.120.98
20300.550.120.98

Routes In Atlantic Northern Forest

Routes recording Mourning 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 →
Old ForgeNEW-YORK111996
HighmarketNEW-YORK92025
AshlandMAINE72008
WanakenaNEW-YORK62025
BaxterMAINE51984
BoundaryMAINE52009
Dexter LakeNEW-YORK51969
Seboomook LkMAINE42014
Ft FairfieldMAINE42005
Weeks BrookMAINE32011
Priestly Br.MAINE32011
Heron LakeMAINE32003
Blue Ridge NNEW-YORK32025
North RiverNEW-YORK32025
St Regis FlsNEW-YORK32017
BiddefordMAINE21976
Wilson MillsMAINE22025
DebloisMAINE21984
NorthfieldMAINE21976
GreenvilleMAINE22006
WaiteMAINE21977
Pillsbury PdMAINE21968
WashburnMAINE22005
St DavidMAINE22005
Big TwentyMAINE22008

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