BirdAnalyst
Species · BCR 22 · BBS 2026 Release · 1966–2025

Marsh Wren In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieForest birds

Marsh Wren in Eastern Tallgrass Prairie has surged: up 350% on the route-weighted index since 1971.

+350%Since 1971TrendPercent 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 →
32Routes 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 →
44YearsYears 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 Eastern Tallgrass Prairie. See the full index history below.

Marsh Wren In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Marsh Wren in Eastern Tallgrass Prairie is projected to fall about 81% by 2030 — from 0.11 in 2025 to a central estimate of 0.02 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±49.1%, with 80% of held-out values landing inside the 95% band.

-81%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 →
0.02Projected 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 →
0.00–0.0895% 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 →
±49.1%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, Marsh Wren in Eastern Tallgrass Prairie is projected to fall about 81% by 2030 — from 0.11 in 2025 to a central estimate of 0.02 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±49.1%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20260.020.000.08
20270.020.000.08
20280.020.000.08
20290.020.000.08
20300.020.000.08

Routes In Eastern Tallgrass Prairie

Routes recording Marsh Wren in Eastern Tallgrass Prairie.
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 →
ComptonILLINOIS62025
BedfordIOWA52025
New LenoxILLINOIS41982
BarringtonILLINOIS32011
MelroseILLINOIS31979
AldenILLINOIS22025
Kankakee SandsINDIANA22025
LakevilleMINNESOTA21999
AustinMINNESOTA22023
RichlandNEBRASKA22016
WayneILLINOIS12024
SherburnvillILLINOIS12016
GulfportILLINOIS12025
ChandlervillILLINOIS11985
BartonvilleILLINOIS12019
AthensvilleILLINOIS12025
SterlingILLINOIS12009
ClaytonILLINOIS12018
GaryINDIANA11997
Portage 2INDIANA12025
West LibertyIOWA12025
WilliamsburgIOWA11996
AliceIOWA11988
Sioux CityIOWA12022
TiptonIOWA12021

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