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Species · Michigan · BBS 2026 Release · 1966–2025

Carolina Wren Population Trend in Michigan

All statesForest birds

Carolina Wren in Michigan has surged: up 888% on the route-weighted index since 1987.

+888%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 →
31Routes 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 →
36YearsYears 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 →

No notable trend signals for Carolina Wren in Michigan. See the full index history below.

Carolina Wren Population Forecast in Michigan

If the recent trend holds, Carolina Wren in Michigan is projected to fall about 50% by 2030 — from 0.52 in 2025 to a central estimate of 0.26 (95% range 0.05–0.47). A 5-year backtest shows a typical error of ±73.8%, with 0% of held-out values landing inside the 95% band.

-50%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 →
0.26Projected 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 →
0.05–0.4795% 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 →
±73.8%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, Carolina Wren in Michigan is projected to fall about 50% by 2030 — from 0.52 in 2025 to a central estimate of 0.26 (95% range 0.05–0.47). A 5-year backtest shows a typical error of ±73.8%, with 0% of held-out values landing inside the 95% band.19752030
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 →
20260.230.030.45
20270.240.030.45
20280.250.040.46
20290.250.040.46
20300.260.050.47

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
Nashville520252000
Belding 2420252017
Holt420252005
Mottville320251976
Bell Oak320052002
Galesburg220251976
Deckerville220132013
Harrietta120192019
New Buffalo120141992
Hamburg 2120252015
Almena120131993
Barry S.G.A.120092009
Scottville120192019
Big Blue Lk120242024
Lawrence120241991
New Troy120221993
Bell Oak 2120252025
Howardsville120252018
Monterey120041991
Rochester120252025
Brush Creek120152015
Ola120182018
Maple Rapids120212021
Fowlerville120062003

Carolina Wren Population Trend in Other States

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

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