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

Chimney Swift Population Trend in Connecticut

All statesAerial insectivores

Chimney Swift in Connecticut has increased: up 34% on the route-weighted index since 1968.

+34%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 →
58YearsYears 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 stay roughly flat through 2029, near 6.7 (95% range 3.4–9.9). A 5-year backtest shows a typical error of ±27.5%, with 100% of held-out values landing inside the 95% band.

+9%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 →
6.7Projected 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 →
3.4–9.995% 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 →
±27.5%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 stay roughly flat through 2029, near 6.7 (95% range 3.4–9.9). A 5-year backtest shows a typical error of ±27.5%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20256.73.49.9
20266.73.49.9
20276.73.49.9
20286.73.49.9
20296.73.49.9

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
Mid Haddam1520241973
New Hartford1419871972
Long Hill1320191973
Uncasville920241977
Southington920241973
Sherman820191972
Greenwich720181968
Granby720241988
Mystic620231973
Westbrook620241969
New Hartford520241994
Danbury420231968
Buckingham320161966
No Woodbury220241967
Woodstock 2220242018
Warren 2220212012
Woodstock120071968
Warren120111973

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 2026-05-22.