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Species · Michigan · BBS 2026 Release · 1966–2025

Swamp Sparrow Population Trend in Michigan

All statesWetland birds

Swamp Sparrow in Michigan has surged: up 445% on the route-weighted index since 1968.

+445%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 MichiganNotable 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 Michigan: up 445% on the route-weighted index since 1968.

Swamp Sparrow Population Forecast in Michigan

If the recent trend holds, Swamp Sparrow in Michigan is projected to rise about 23% by 2030 — from 2.2 in 2025 to a central estimate of 2.7 (95% range 1.8–3.7). A 5-year backtest shows a typical error of ±28.8%, with 80% of held-out values landing inside the 95% band.

+23%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 →
2.7Projected 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 →
1.8–3.795% 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 →
±28.8%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, Swamp Sparrow in Michigan is projected to rise about 23% by 2030 — from 2.2 in 2025 to a central estimate of 2.7 (95% range 1.8–3.7). A 5-year backtest shows a typical error of ±28.8%, 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 →
20262.61.73.6
20272.71.73.6
20282.71.73.7
20292.71.73.7
20302.71.83.7

Swamp Sparrow Survey Routes in Michigan

Routes recording Swamp Sparrow in Michigan.
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 →
Muskallonge1120241977
Chippewa Lk.1020251992
Maple Grove920251974
Brocky Lake920251980
Nashville820251968
Tahquamenon720251974
Seney Nwr720251992
Galesburg620251966
Howardsville620251971
Pettysville619791969
Lapeer620252000
Marenisco520191981
Herman520151983
Walloon Lake 2520242005
Pine River520181992
Pleasant Val419911986
Hubbard Lake419931974
Cohoctah420252021
Hamburg420011981
Sidnaw420251993
Almena420151993
Cunard320181981
Belding320001983
Raco320251972
Walloon Lake320041977

Swamp Sparrow Population Trend in Other States

connecticutdelawareillinoisindianaiowamainemarylandmassachusettsminnesotanebraskanew-hampshirenew-jerseynew-yorknorth-dakotaohiopennsylvaniarhode-islandsouth-dakotavermontvirginiawest-virginiawisconsin

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