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

Swamp Sparrow Population Trend in Wisconsin

All statesWetland birds

Swamp Sparrow in Wisconsin has increased: up 46% on the route-weighted index since 1968.

+46%Since 1968TrendPercent 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 →
92Routes 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 →
59YearsYears 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 WisconsinNotable 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 Swamp Sparrow in Wisconsin. See the full index history below.

Swamp Sparrow Population Forecast in Wisconsin

If the recent trend holds, Swamp Sparrow in Wisconsin is projected to stay roughly flat through 2030, near 2.3 (95% range 1.6–3.0). A 5-year backtest shows a typical error of ±25.1%, with 80% 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 →
2.3Projected 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 →
1.6–3.095% 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 →
±25.1%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 Wisconsin is projected to stay roughly flat through 2030, near 2.3 (95% range 1.6–3.0). A 5-year backtest shows a typical error of ±25.1%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20262.31.53.0
20272.31.53.0
20282.31.53.0
20292.31.63.0
20302.31.63.0

Swamp Sparrow Survey Routes in Wisconsin

Routes recording Swamp Sparrow in Wisconsin.
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 →
Omro 21620252002
Mather1320231966
Weirgor Springs1020251999
Loraine920251968
Briggsville820251999
Gilman720251966
Pardeeville720251967
Flambeau720251998
Kiel720251998
Cumberland620251966
Unity620251970
Hebron620251966
Land O' Lakes 2620252017
Gilmanton519881977
Mount Horeb519901967
Annaton520251998
Chaffey420251968
Shanagolden420251969
Weyerhauser420251976
Couderay420251973
Holway419891967
Omro420011966
Minong320251967
Montreal320231968
Exeland320251968

Swamp Sparrow Population Trend in Other States

connecticutdelawareillinoisindianaiowamainemarylandmassachusettsmichiganminnesotanebraskanew-hampshirenew-jerseynew-yorknorth-dakotaohiopennsylvaniarhode-islandsouth-dakotavermontvirginiawest-virginia

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