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

Swamp Sparrow Population Trend in North Dakota

All statesGeneralists

Swamp Sparrow in North Dakota has surged: up 708% on the route-weighted index since 1974.

+708%Since 1974TrendPercent 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 →
20Routes 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 →
38YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Swamp Sparrow 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 →

Swamp Sparrow has surged in North Dakota: up 708% on the route-weighted index since 1974.

Swamp Sparrow Population Forecast in North Dakota

If the recent trend holds, Swamp Sparrow in North Dakota is projected to fall about 13% by 2029 — from 0.48 in 2024 to a central estimate of 0.42 (95% range 0.10–0.73). A 5-year backtest shows a typical error of ±38.2%, with 80% of held-out values landing inside the 95% band.

-13%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 →
0.42Projected 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 →
0.10–0.7395% 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 →
±38.2%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, Swamp Sparrow in North Dakota is projected to fall about 13% by 2029 — from 0.48 in 2024 to a central estimate of 0.42 (95% range 0.10–0.73). A 5-year backtest shows a typical error of ±38.2%, with 80% of held-out values landing inside the 95% band.19692029
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 →
20250.390.070.70
20260.390.080.71
20270.400.090.72
20280.410.100.72
20290.420.100.73

Swamp Sparrow Survey Routes in North Dakota

Routes recording Swamp Sparrow 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 Lk520241981
Edgeley320242012
Forman220221969
Wimbledon220222012
Buchanan220232016
Nash219971988
Sheyenne Lk220241988
Walcott120132012
Lake George120192019
Kempton120051997
Emerado120221995
Cooperstown120242005
Lakota119981988
Regan120182015
Denbigh120241987
Powers Lake120222022
Douglas Crk120212012
Braddock119921989
Turtle Mtns120242000
Danzig 2120192019

Swamp Sparrow Population Trend in Other States

connecticutdelawareillinoisindianaiowamainemarylandmassachusettsmichiganminnesotanebraskanew-hampshirenew-jerseynew-yorkohiopennsylvaniarhode-islandsouth-dakotavermontvirginiawest-virginiawisconsin

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