BirdAnalyst
Species · North Dakota · BBS 2025 Release · 1966–2024

Marsh Wren Population Trend in North Dakota

All statesForest birds

Marsh Wren in North Dakota has surged: up 924% on the route-weighted index since 1969.

+924%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 →
57YearsYears 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 924% 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 fall about 14% by 2029 — from 22 in 2024 to a central estimate of 19 (95% range 14–24). A 5-year backtest shows a typical error of ±11.8%, with 100% of held-out values landing inside the 95% band.

-14%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 →
19Projected 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 →
14–2495% 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 →
±11.8%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 fall about 14% by 2029 — from 22 in 2024 to a central estimate of 19 (95% range 14–24). A 5-year backtest shows a typical error of ±11.8%, with 100% of held-out values landing inside the 95% band.19672029
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 →
2025181223
2026181323
2027181324
2028191324
2029191424

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 Lk21620241980
Buchanan7320241967
Sheyenne Lk7220241980
Forman5420241968
Lakota4820091968
Danzig 22920242019
Danzig2720131982
Wimbledon2620241981
Edgeley2420241987
Montpelier2220241990
Cooperstown1920241969
Regan1820221969
Lakota 21820242010
Braddock1720221988
Powers Lake1520241980
Niles1420231989
Loraine920191986
Turtle Mtns820241981
Parshall620131982
Lake George520221967
Dunn Center520161968
Rolla420241969
Carpio420231973
Wild Rose420241985
Nash319991981

Marsh Wren Population Trend in Other States

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

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