BirdAnalyst
Species · Michigan · BBS 2025 Release · 1966–2024

Swamp Sparrow Population Trend in Michigan

All statesGeneralists

Swamp Sparrow in Michigan has surged: up 449% on the route-weighted index since 1968.

+449%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 →
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 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 449% 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 15% by 2029 — from 2.4 in 2024 to a central estimate of 2.8 (95% range 1.8–3.7). A 5-year backtest shows a typical error of ±26.6%, with 80% of held-out values landing inside the 95% band.

+15%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 →
2.8Projected 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 →
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 →
±26.6%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 15% by 2029 — from 2.4 in 2024 to a central estimate of 2.8 (95% range 1.8–3.7). A 5-year backtest shows a typical error of ±26.6%, with 80% of held-out values landing inside the 95% band.19662029
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 →
20252.61.73.6
20262.71.73.7
20272.71.73.7
20282.71.73.7
20292.81.83.7

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.1020241992
Ned Lake720241986
Brocky Lake720241980
Seney Nwr720241992
Nashville620241968
Galesburg620241966
Howardsville620241971
Pettysville619791969
Marenisco520191981
Herman520151983
Tahquamenon520241974
Walloon Lake 2520242005
Lapeer520242000
Pine River520181992
Lawrence420241974
Pleasant Val419911986
Hubbard Lake419931974
Hamburg420011981
Almena420151993
Gibbs City320241982
Maple Grove320241974
Cunard320181981
Belding320001983
Mottville320241969

Swamp Sparrow Population Trend in Other States

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

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