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Species · Michigan · BBS 2025 Release · 1966–2024

Carolina Wren Population Trend in Michigan

All statesForest birds

Carolina Wren in Michigan has surged: up 756% on the route-weighted index since 1987.

+756%Since 1987TrendPercent 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 →
29Routes 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 →
35YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Carolina 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 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 →

Carolina Wren has surged in Michigan: up 755% on the route-weighted index since 1987.

Carolina Wren Population Forecast in Michigan

If the recent trend holds, Carolina Wren in Michigan is projected to fall about 60% by 2029 — from 0.55 in 2024 to a central estimate of 0.22 (95% range 0.03–0.40). A 5-year backtest shows a typical error of ±70.9%, with 0% of held-out values landing inside the 95% band.

-60%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 →
0.22Projected 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 →
0.03–0.4095% 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 →
±70.9%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, Carolina Wren in Michigan is projected to fall about 60% by 2029 — from 0.55 in 2024 to a central estimate of 0.22 (95% range 0.03–0.40). A 5-year backtest shows a typical error of ±70.9%, with 0% of held-out values landing inside the 95% band.19752029
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 →
20250.200.010.38
20260.200.020.39
20270.210.020.39
20280.210.030.40
20290.220.030.40

Carolina Wren Survey Routes in Michigan

Routes recording Carolina 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 →
Homer620241992
Galesburg520241976
Belding 2420242017
Mottville420241976
Nashville320242000
Bell Oak320052002
Deckerville220132013
Harrietta120192019
New Buffalo120141992
Hamburg 2120242015
Almena120131993
Barry S.G.A.120092009
Scottville120192019
Big Blue Lk120242024
Lawrence120241991
New Troy120221993
Howardsville120222018
Monterey120041991
Brush Creek120152015
Ola120182018
Maple Rapids120212021
Holt120052005
Fowlerville120062003
Adrian120182004
Prattville120211987

Carolina Wren Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsin

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