BirdAnalyst
Species · New Jersey · BBS 2025 Release · 1966–2024

Green Heron Population Trend in New Jersey

All statesWetland birds

Green Heron in New Jersey has fallen sharply: down 57% on the route-weighted index since 1968.

-57%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 →
39Routes 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 Green Heron Trends in New JerseyNotable 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 →

Green Heron has fallen sharply in New Jersey: down 57% on the route-weighted index since 1968.

Green Heron Population Forecast in New Jersey

If the recent trend holds, Green Heron in New Jersey is projected to fall about 63% by 2029 — from 0.24 in 2024 to a central estimate of 0.09 (95% range 0.00–0.51). A 5-year backtest shows a typical error of ±31.9%, with 100% of held-out values landing inside the 95% band.

-63%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 →
0.09Projected 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 →
0.00–0.5195% 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 →
±31.9%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, Green Heron in New Jersey is projected to fall about 63% by 2029 — from 0.24 in 2024 to a central estimate of 0.09 (95% range 0.00–0.51). A 5-year backtest shows a typical error of ±31.9%, 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 →
20250.140.000.55
20260.120.000.54
20270.110.000.53
20280.100.000.52
20290.090.000.51

Green Heron Survey Routes in New Jersey

Routes recording Green Heron in New Jersey.
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 →
Bennett Mill619761967
Deepwater519771969
Spraguetown519831980
Del Haven319911991
Kemah Lake320241967
Six Points220151978
Robbinsville219791979
Midvale220061967
Villas219801979
Croton 2220162016
Woodbury Hgt120091968
Greenwich120211966
Toms River120091967
Albion120111968
Ancora119761972
Sandbrook120001969
Holmansville119961969
Clarksville119841972
New Bedford120241973
Croton119991973
Hope119941970
Bloomsbury120131976
High Point120211978
Dover120221977
Pottersville120131983

Green Heron Population Trend in Other States

alabamaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsin

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