BirdAnalyst
Species · Oregon · BBS 2026 Release · 1966–2025

Marsh Wren Population Trend in Oregon

All statesForest birds

Marsh Wren in Oregon has declined: down 27% on the route-weighted index since 1973.

-27%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 →
34Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Marsh Wren Trends in OregonNotable 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 Oregon. See the full index history below.

Marsh Wren Population Forecast in Oregon

If the recent trend holds, Marsh Wren in Oregon is projected to rise about 121% by 2030 — from 0.38 in 2025 to a central estimate of 0.83 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±88.6%, with 100% of held-out values landing inside the 95% band.

+121%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 →
0.83Projected 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 →
0.00–1.795% 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 →
±88.6%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 Oregon is projected to rise about 121% by 2030 — from 0.38 in 2025 to a central estimate of 0.83 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±88.6%, with 100% of held-out values landing inside the 95% band.19712030
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 →
20260.830.001.7
20270.830.001.7
20280.830.001.7
20290.830.001.7
20300.830.001.7

Marsh Wren Survey Routes in Oregon

Routes recording Marsh Wren in Oregon.
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 →
Merrill1320221993
Fish Lake1120251972
Glasgow1120251986
Princeton919851973
Chinchalo520251993
Malheur Nwr419981986
Umatilla420231988
Nicolai Mtn.320251993
Hauser319851971
Blizzard Gap320252000
Madras320171997
Coquille320251994
Lone Rock219971997
Ordnance219791972
Wedderburn219971997
Bly 2220222007
Svensen219921990
Warner Vally220181994
Salem220162012
Molalla120252025
Summit Pr120052005
Scappoose120211995
Lapham Res.119961996
Umpqua119981983
Modoc Point120181995

Marsh Wren Population Trend in Other States

alabamaarizonacaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandsouth-carolinasouth-dakotatexasutahvermontvirginiawashingtonwisconsinwyoming

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