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

Marsh Wren Population Trend in Michigan

All statesForest birds

Marsh Wren in Michigan has fallen sharply: down 51% on the route-weighted index since 1971.

-51%Since 1971TrendPercent 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 →
25Routes 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 →
46YearsYears 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 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 declinecomputed 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 fallen sharply in Michigan: down 51% on the route-weighted index since 1971.

Marsh Wren Population Forecast in Michigan

If the recent trend holds, Marsh Wren in Michigan is projected to stay roughly flat through 2028, near 0.01 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±80.3%, with 80% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.01Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1295% 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 →
±80.3%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 Michigan is projected to stay roughly flat through 2028, near 0.01 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±80.3%, with 80% of held-out values landing inside the 95% band.19682028
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 →
20240.020.000.12
20250.020.000.12
20260.020.000.12
20270.020.000.12
20280.010.000.12

Marsh Wren Survey Routes in Michigan

Routes recording Marsh Wren 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 →
Pettysville419791976
Rochester220022000
Hamburg219931990
S Lyons219741971
Cohoctah220212021
Marenisco120151990
Chippewa Lk.120062005
Seney Nwr119961994
Brocky Lake120132013
Barry S.G.A.120092008
Big Blue Lk120181994
Gilchrist119951995
Skegemog Pt120112011
Nashville120181972
Belding119851984
Galesburg120191968
Howardsville120231976
Monterey119901985
Lapeer120002000
Mottville120231971
Hartland119981993
Bell Oak119691969
Holt119861986
Prattville120022002
Juniata120041979

Marsh Wren Population Trend in Other States

alabamaarizonacaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamainemarylandmassachusettsminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatexasutahvermontvirginiawashingtonwisconsinwyoming

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