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

Northern Cardinal Population Trend in Connecticut

All statesGeneralists

Northern Cardinal in Connecticut has surged: up 279% on the route-weighted index since 1968.

+279%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 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 279% 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 58% by 2029 — from 21 in 2024 to a central estimate of 33 (95% range 26–41). A 5-year backtest shows a typical error of ±37.4%, with 20% of held-out values landing inside the 95% band.

+58%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 →
33Projected 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 →
26–4195% 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 →
±37.4%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 58% by 2029 — from 21 in 2024 to a central estimate of 33 (95% range 26–41). A 5-year backtest shows a typical error of ±37.4%, with 20% 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 →
2025322439
2026322439
2027322540
2028332540
2029332641

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
Southington4020241973
Mystic3720231973
Danbury3420231968
Greenwich2720181967
Uncasville2620241973
Buckingham2520221967
Westbrook2520241969
Mid Haddam2320241973
New Hartford2020241994
No Woodbury1720241967
E Hartland1619921966
Granby1520241988
Woodstock1420071970
Warren 21320242012
Sherman1220191972
Woodstock 21020242016
New Hartford819871972

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 2026-05-22.