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

Carolina Wren Population Trend in Massachusetts

All statesForest birds

Carolina Wren in Massachusetts has surged: up 73× on the route-weighted index since 1971.

73×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 →
27Routes 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 →
52YearsYears 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 MassachusettsNotable 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 Massachusetts: up 73× on the route-weighted index since 1971.

Carolina Wren Population Forecast in Massachusetts

If the recent trend holds, Carolina Wren in Massachusetts is projected to fall about 24% by 2030 — from 10 in 2025 to a central estimate of 7.7 (95% range 4.6–11). A 5-year backtest shows a typical error of ±43.3%, with 20% of held-out values landing inside the 95% band.

-24%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 →
7.7Projected 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 →
4.6–1195% 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 →
±43.3%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, Carolina Wren in Massachusetts is projected to fall about 24% by 2030 — from 10 in 2025 to a central estimate of 7.7 (95% range 4.6–11). A 5-year backtest shows a typical error of ±43.3%, with 20% of held-out values landing inside the 95% band.19662030
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 →
20267.14.010
20277.34.110
20287.44.311
20297.64.411
20307.74.611

Carolina Wren Survey Routes in Massachusetts

Routes recording Carolina Wren in Massachusetts.
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 →
Gay Head2920251996
Maynard2520251990
Marion2420251971
Prattville2120191966
Mansfield2020251975
Belchertown1920252005
Wellfleet 21520252016
Newburyport1220221993
S Barre1220252001
Monterey720242019
E Dennis520211970
N Oxford520251994
Sheffield520222002
N. Andover520252002
Brockton420191989
Littleton420251992
Chilmark319831971
Wellfleet320071987
N Orange320242014
Chesterfield320241984
Holden320251992
Warren220091985
Warren 2220252010
Ware River120142013
Cape Cod Ns119991991

Carolina Wren Population Trend in Other States

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

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