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

Northern Cardinal Population Trend in Connecticut

All statesForest birds

Northern Cardinal in Connecticut has surged: up 261% on the route-weighted index since 1968.

+261%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 Northern Cardinal 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 →

Northern Cardinal has surged in Connecticut: up 261% on the route-weighted index since 1968.

Northern Cardinal Population Forecast in Connecticut

If the recent trend holds, Northern Cardinal in Connecticut is projected to rise about 54% by 2030 — from 21 in 2025 to a central estimate of 33 (95% range 25–41). A 5-year backtest shows a typical error of ±42.9%, with 0% of held-out values landing inside the 95% band.

+54%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 →
33Projected 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 →
25–4195% 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 →
±42.9%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, Northern Cardinal in Connecticut is projected to rise about 54% by 2030 — from 21 in 2025 to a central estimate of 33 (95% range 25–41). A 5-year backtest shows a typical error of ±42.9%, with 0% 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 →
2026312339
2027322439
2028322440
2029322440
2030332541

Northern Cardinal Survey Routes in Connecticut

Routes recording Northern Cardinal 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 →
Willimantic7220181967
Warren6420111972
Long Hill4520191972
Mystic3720231973
Danbury3420231968
Southington3420251973
Greenwich2720181967
Buckingham2520221967
Uncasville2420251973
Westbrook2320251969
Mid Haddam2320251973
No Woodbury2120251967
Woodstock 22120252016
New Hartford2020241994
Granby1720251988
E Hartland1619921966
Woodstock1420071970
Sherman1220191972
New Hartford819871972
Warren 2720252012

Northern Cardinal Population Trend in Other States

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

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