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

Marsh Wren In Atlantic Northern Forest

All regionsAtlantic Northern ForestForest birds

Marsh Wren in Atlantic Northern Forest has surged: up 92% on the route-weighted index since 1973.

+92%Since 1973TrendPercent 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 →
49YearsYears 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 Marsh Wren in Atlantic Northern Forest. See the full index history below.

Forecast

If the recent trend holds, Marsh Wren in Atlantic Northern Forest is projected to stay roughly flat through 2029, near 0.08 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±195.6%, 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 →
0.08Projected 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 →
0.00–0.1595% 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 →
±195.6%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, Marsh Wren in Atlantic Northern Forest is projected to stay roughly flat through 2029, near 0.08 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±195.6%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.070.000.15
20260.070.000.15
20270.070.000.15
20280.070.000.15
20290.080.000.15

Routes In Atlantic Northern Forest

Routes recording Marsh Wren 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 →
WarrenMAINE21990
Underwood 2NEW-YORK22008
S WallingfrdVERMONT22022
W RutlandVERMONT22024
BiddefordMAINE11981
Bowdoin CtrMAINE11994
HarmonyMAINE12007
CarrabassettMAINE12017
CharlestonMAINE12009
HudsonMAINE11997
WashburnMAINE11994
JeffersonMAINE12010
SheffieldMASSACHUSETTS12013
PeterboroughNEW-HAMPSHIRE11985
HopkintonNEW-HAMPSHIRE11968
WilmotNEW-HAMPSHIRE11994
WalpoleNEW-HAMPSHIRE12006
MarlowNEW-HAMPSHIRE11982
PetersburgNEW-YORK11990
Number FourNEW-YORK11971
WarrensburgNEW-YORK11977
DegrasseNEW-YORK12023
LandgroveVERMONT12017
Post MillsVERMONT12018

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