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

Carolina Wren Population Trend in Connecticut

All statesForest birds

Carolina Wren in Connecticut has surged: up 33× on the route-weighted index since 1976.

33×Since 1976TrendPercent 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 →
20Routes 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 →
49YearsYears 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 ConnecticutNotable 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 Connecticut: up 33× on the route-weighted index since 1976.

Carolina Wren Population Forecast in Connecticut

If the recent trend holds, Carolina Wren in Connecticut is projected to fall about 31% by 2029 — from 10 in 2024 to a central estimate of 7.1 (95% range 4.4–9.8). A 5-year backtest shows a typical error of ±37.4%, with 40% of held-out values landing inside the 95% band.

-31%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 →
7.1Projected 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 →
4.4–9.895% 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 →
±37.4%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 Connecticut is projected to fall about 31% by 2029 — from 10 in 2024 to a central estimate of 7.1 (95% range 4.4–9.8). A 5-year backtest shows a typical error of ±37.4%, with 40% of held-out values landing inside the 95% band.19742029
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 →
20256.63.89.3
20266.74.09.4
20276.84.19.6
20287.04.39.7
20297.14.49.8

Carolina Wren Survey Routes in Connecticut

Routes recording Carolina Wren in Connecticut.
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 →
Long Hill2020191982
Westbrook1820241977
Uncasville1720241988
Danbury1720232005
Mid Haddam1420241990
Mystic1120231974
Buckingham920221975
Woodstock 2920242017
Granby920241991
Southington720241990
New Hartford720242007
Warren 2720242023
No Woodbury520241993
Greenwich520181976
Sherman320191989
Willimantic220181975
E Hartland119921992
Woodstock119941991
Warren120111991
New Hartford119781976

Carolina Wren Population Trend in Other States

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

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