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

Great Blue Heron Population Trend in Connecticut

All statesWetland birds

Great Blue Heron in Connecticut has surged: up 768% on the route-weighted index since 1975.

+768%Since 1975
18Routes In State
49Years

Notable Great Blue Heron Trends in Connecticut

long arc increasecomputed index

Great Blue Heron has surged in Connecticut: up 768% on the route-weighted index since 1975.

Great Blue Heron Population Forecast in Connecticut

If the recent trend holds, Great Blue Heron in Connecticut is projected to rise about 103% by 2029 — from 0.56 in 2024 to a central estimate of 1.1 (95% range 0.57–1.7). A 5-year backtest shows a typical error of ±37.1%, with 80% of held-out values landing inside the 95% band.

+103%Change by 2029
1.1Projected 2029 index
0.57–1.795% range
±37.1%Backtest error
19732029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20251.00.491.6
20261.10.511.6
20271.10.531.6
20281.10.551.7
20291.10.571.7

Great Blue Heron Survey Routes in Connecticut

Routes recording Great Blue Heron in Connecticut.
Woodstock320071976
Buckingham220141993
Uncasville220231999
Willimantic220141991
Danbury220232006
Southington220242008
Warren 2220152012
Mystic120231973
New Hartford120231994
Westbrook120241991
No Woodbury120141983
Sherman120191985
Greenwich119831983
Warren120111993
Long Hill120191975
Mid Haddam120241973
Woodstock 2120242017
Granby120231988

Great Blue Heron Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradodelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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