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

Blue Jay Population Trend in Connecticut

All statesGeneralists

Blue Jay in Connecticut has fallen sharply: down 61% on the route-weighted index since 1968.

-61%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 Blue Jay 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 declinecomputed 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 →

Blue Jay has fallen sharply in Connecticut: down 61% on the route-weighted index since 1968.

Blue Jay Population Forecast in Connecticut

If the recent trend holds, Blue Jay in Connecticut is projected to fall about 35% by 2029 — from 10 in 2024 to a central estimate of 6.7 (95% range 0.91–13). A 5-year backtest shows a typical error of ±21.9%, with 100% of held-out values landing inside the 95% band.

-35%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 →
0.91–1395% 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 →
±21.9%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, Blue Jay in Connecticut is projected to fall about 35% by 2029 — from 10 in 2024 to a central estimate of 6.7 (95% range 0.91–13). A 5-year backtest shows a typical error of ±21.9%, 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 →
20257.71.914
20267.51.713
20277.21.413
20287.01.213
20296.70.9113

Blue Jay Survey Routes in Connecticut

Routes recording Blue Jay 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 →
Southington2120241973
Westbrook2020241969
Warren1920111972
Willimantic1620181967
Greenwich1420181967
New Hartford1319871972
Woodstock 21220242016
Mystic1120231973
Danbury1120231968
Uncasville920241973
Mid Haddam920241973
Long Hill820191972
Buckingham720221966
Granby720241988
E Hartland619921966
Woodstock620071968
No Woodbury620241967
Sherman620191972
New Hartford520241994
Warren 2420242012

Blue Jay Population Trend in Other States

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

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