BirdAnalyst
Species · Maine · BBS 2026 Release · 1966–2025

Carolina Wren Population Trend in Maine

All statesForest birds

Carolina Wren in Maine has surged: up 16× on the route-weighted index since 2000.

16×Since 2000TrendPercent 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 →
11Routes 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 →
22YearsYears 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 MaineNotable 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 Maine. See the full index history below.

Carolina Wren Population Forecast in Maine

If the recent trend holds, Carolina Wren in Maine is projected to rise about 14% by 2030 — from 0.33 in 2025 to a central estimate of 0.38 (95% range 0.08–0.68). A 5-year backtest shows a typical error of ±69.8%, with 0% of held-out values landing inside the 95% band.

+14%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 →
0.38Projected 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 →
0.08–0.6895% 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 →
±69.8%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 Maine is projected to rise about 14% by 2030 — from 0.33 in 2025 to a central estimate of 0.38 (95% range 0.08–0.68). A 5-year backtest shows a typical error of ±69.8%, with 0% of held-out values landing inside the 95% band.19922030
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 →
20260.330.030.63
20270.340.040.64
20280.350.050.66
20290.370.070.67
20300.380.080.68

Carolina Wren Survey Routes in Maine

Routes recording Carolina Wren in Maine.
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 →
Cape Neddick620232005
Kittery Pt520251992
Northfield 2220142014
Carrabassett120172017
Westbrook120241992
Otisfield Gr120122012
Hartford120142014
Bowdoin Ctr120132013
Turner 2120252025
Freedom120212021
Brooks120212021

Carolina Wren Population Trend in Other States

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

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