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Species · BCR 19 · BBS 2026 Release · 1966–2025

Marsh Wren In Central Mixed Grass Prairie

All regionsCentral Mixed Grass PrairieForest birds

Marsh Wren in Central Mixed Grass Prairie has surged: up 143% on the route-weighted index since 1970.

+143%Since 1970TrendPercent 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 →
15Routes 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 →

long arc increasecomputed 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 →

Marsh Wren has surged in Central Mixed Grass Prairie: up 143% on the route-weighted index since 1970.

Marsh Wren In Central Mixed Grass Prairie Population Forecast

If the recent trend holds, Marsh Wren in Central Mixed Grass Prairie is projected to fall about 12% by 2030 — from 0.51 in 2025 to a central estimate of 0.45 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±316.2%, with 100% of held-out values landing inside the 95% band.

-12%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 →
0.45Projected 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 →
0.00–1.295% 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 →
±316.2%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 Central Mixed Grass Prairie is projected to fall about 12% by 2030 — from 0.51 in 2025 to a central estimate of 0.45 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±316.2%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.450.001.2
20270.450.001.2
20280.450.001.2
20290.450.001.2
20300.450.001.2

Routes In Central Mixed Grass Prairie

Routes recording Marsh Wren in Central Mixed Grass 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 →
Crescent LkNEBRASKA252025
NenzelNEBRASKA82025
ChambersNEBRASKA42023
AlbertKANSAS32014
Piester LakeNEBRASKA31992
MullenNEBRASKA32023
BrownleeNEBRASKA22025
Wheeler CoNEBRASKA22025
St JohnKANSAS12003
SolomonKANSAS11991
SurpriseNEBRASKA12021
Swan LakeNEBRASKA12000
JohnstownNEBRASKA11999
KennedyNEBRASKA12022
GordonNEBRASKA12011

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