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

Chimney Swift Population Trend in Connecticut

All statesAerial insectivores

Chimney Swift in Connecticut has edged up: up 21% on the route-weighted index since 1968.

+21%Since 1968TrendPercent 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Chimney Swift 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 →

No notable trend signals for Chimney Swift in Connecticut. See the full index history below.

Chimney Swift Population Forecast in Connecticut

If the recent trend holds, Chimney Swift in Connecticut is projected to rise about 17% by 2030 — from 5.6 in 2025 to a central estimate of 6.6 (95% range 3.3–9.8). A 5-year backtest shows a typical error of ±28.2%, with 100% of held-out values landing inside the 95% band.

+17%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 →
6.6Projected 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 →
3.3–9.895% 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 →
±28.2%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, Chimney Swift in Connecticut is projected to rise about 17% by 2030 — from 5.6 in 2025 to a central estimate of 6.6 (95% range 3.3–9.8). A 5-year backtest shows a typical error of ±28.2%, with 100% 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 →
20266.63.39.8
20276.63.39.8
20286.63.39.8
20296.63.39.8
20306.63.39.8

Chimney Swift Survey Routes in Connecticut

Routes recording Chimney Swift 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 →
Willimantic1720181967
E Hartland1519921966
New Hartford1419871972
Long Hill1320191973
Uncasville1220251977
Granby1120251988
Southington1020251973
Sherman820191972
Greenwich720181968
Mystic620231973
Westbrook520251969
New Hartford520241994
Danbury420231968
Mid Haddam420251973
Buckingham320161966
No Woodbury220241967
Warren 2220252012
Woodstock120071968
Warren120111973
Woodstock 2120252018

Chimney Swift Population Trend in Other States

alabamaarkansascoloradodelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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