BirdAnalyst
Species · BCR 13 · BBS 2025 Release · 1966–2024

Marsh Wren In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainForest birds

Marsh Wren in Lower Great Lakes / St. Lawrence Plain has increased: up 41% on the route-weighted index since 1968.

+41%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 →
31Routes 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 →
50YearsYears 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 Lower Great Lakes / St. Lawrence Plain. See the full index history below.

Forecast

If the recent trend holds, Marsh Wren in Lower Great Lakes / St. Lawrence Plain is projected to fall about 16% by 2029 — from 0.19 in 2024 to a central estimate of 0.16 (95% range 0.00–0.40). A 5-year backtest shows a typical error of ±23.6%, with 100% of held-out values landing inside the 95% band.

-16%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 →
0.16Projected 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 →
0.00–0.4095% 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 →
±23.6%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 Lower Great Lakes / St. Lawrence Plain is projected to fall about 16% by 2029 — from 0.19 in 2024 to a central estimate of 0.16 (95% range 0.00–0.40). A 5-year backtest shows a typical error of ±23.6%, 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 →
20250.160.000.40
20260.160.000.40
20270.160.000.40
20280.160.000.40
20290.160.000.40

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Marsh Wren in Lower Great Lakes / St. Lawrence Plain.
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 →
PhiladelphiaNEW-YORK82024
HinesburgVERMONT81994
BristolVERMONT32000
Cicero CtrNEW-YORK21995
North EastonNEW-YORK22017
Herner CrnsOHIO21988
New SomersetOHIO21987
RhinebeckNEW-YORK12015
W ShokanNEW-YORK11989
Ballston LkNEW-YORK11970
Oriskany FlsNEW-YORK12005
OrleansNEW-YORK12012
MendonNEW-YORK12017
West SenecaNEW-YORK12004
CastileNEW-YORK12017
RandolphNEW-YORK11968
ByronNEW-YORK12023
ChurchvilleNEW-YORK11968
WatertownNEW-YORK12009
N WilmurtNEW-YORK11970
OgdensburgNEW-YORK12024
ParishvilleNEW-YORK12021
NaplesNEW-YORK12022
CrescentNEW-YORK11999
Harris HillNEW-YORK12022

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