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Species · Connecticut · BBS 2026 Release · 1966–2025

Eastern Bluebird Population Trend in Connecticut

All statesForest birds

Eastern Bluebird in Connecticut has surged: up 250% on the route-weighted index since 1968.

+250%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 Eastern Bluebird 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 →

Eastern Bluebird has surged in Connecticut: up 250% on the route-weighted index since 1968.

Eastern Bluebird Population Forecast in Connecticut

If the recent trend holds, Eastern Bluebird in Connecticut is projected to rise about 14% by 2030 — from 3.5 in 2025 to a central estimate of 4.0 (95% range 2.5–5.5). A 5-year backtest shows a typical error of ±29.5%, with 40% 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 →
4.0Projected 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 →
2.5–5.595% 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 →
±29.5%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, Eastern Bluebird in Connecticut is projected to rise about 14% by 2030 — from 3.5 in 2025 to a central estimate of 4.0 (95% range 2.5–5.5). A 5-year backtest shows a typical error of ±29.5%, with 40% 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 →
20263.72.35.2
20273.82.35.3
20283.92.45.3
20293.92.45.4
20304.02.55.5

Eastern Bluebird Survey Routes in Connecticut

Routes recording Eastern Bluebird 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 →
Buckingham820221971
Sherman820191973
Mystic620231973
Greenwich620181967
Willimantic520181967
Mid Haddam520251973
Woodstock 2520252016
Uncasville420251973
Warren 2420252012
Westbrook320251969
No Woodbury320251967
Granby320251989
Woodstock220071974
Danbury220231972
E Hartland119901966
Warren120111976
Long Hill120191973
Southington120251978
New Hartford119871972
New Hartford120242010

Eastern Bluebird Population Trend in Other States

alabamaarizonaarkansascoloradodelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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