BirdAnalyst
Species · North Dakota · BBS 2026 Release · 1966–2025

Marsh Wren Population Trend in North Dakota

All statesForest birds

Marsh Wren in North Dakota has surged: up 977% on the route-weighted index since 1969.

+977%Since 1969TrendPercent 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 →
47Routes 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 →
58YearsYears 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 North DakotaNotable 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 North Dakota: up 977% on the route-weighted index since 1969.

Marsh Wren Population Forecast in North Dakota

If the recent trend holds, Marsh Wren in North Dakota is projected to stay roughly flat through 2030, near 19 (95% range 14–25). A 5-year backtest shows a typical error of ±10.4%, with 100% of held-out values landing inside the 95% band.

-3%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 →
19Projected 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 →
14–2595% 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 →
±10.4%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 North Dakota is projected to stay roughly flat through 2030, near 19 (95% range 14–25). A 5-year backtest shows a typical error of ±10.4%, with 100% 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 →
2026181323
2027181324
2028191424
2029191424
2030191425

Marsh Wren Survey Routes in North Dakota

Routes recording Marsh Wren in North Dakota.
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 →
Horsehead Lk19120251980
Lakota4820091968
Wimbledon4620251981
Sheyenne Lk4320251980
Forman3620251968
Buchanan3520251967
Montpelier3420251990
Cooperstown3120251969
Regan3020251969
Edgeley2820251987
Danzig2720131982
Powers Lake2220251980
Danzig 22220252019
Lakota 21820242010
Braddock1720231988
Niles1420231989
Turtle Mtns1220251981
Lake George1020231967
Loraine920191986
Denbigh920251972
Parshall620131982
Dunn Center520161968
Rolla420241969
Carpio420231973
Wild Rose420241985

Marsh Wren Population Trend in Other States

alabamaarizonacaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatexasutahvermontvirginiawashingtonwisconsinwyoming

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