BirdAnalyst
Species · New Jersey · BBS 2026 Release · 1966–2025

Black-crowned Night Heron Population Trend in New Jersey

All statesWetland birds

Black-crowned Night Heron in New Jersey has fallen sharply: down 55% on the route-weighted index since 1971.

-55%Since 1971TrendPercent 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 →
13Routes 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 →
38YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-crowned Night 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 →

Black-crowned Night Heron has fallen sharply in New Jersey: down 55% on the route-weighted index since 1971.

Black-crowned Night Heron Population Forecast in New Jersey

If the recent trend holds, Black-crowned Night Heron in New Jersey is projected to stay roughly flat through 2030, near 0.11 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±69%, with 100% of held-out values landing inside the 95% band.

-1%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 →
0.11Projected 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 →
0.00–0.3995% 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 →
±69%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, Black-crowned Night Heron in New Jersey is projected to stay roughly flat through 2030, near 0.11 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±69%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.120.000.40
20270.120.000.40
20280.120.000.40
20290.110.000.39
20300.110.000.39

Black-crowned Night Heron Survey Routes in New Jersey

Routes recording Black-crowned Night 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 →
Spraguetown519971997
Villas319811980
Deepwater219711970
Ancora219701970
Cape May Ch220111992
Ocean City220251979
Greenwich119681968
Six Points119991978
Toms River120072007
Albion119721971
Pedricktown120031993
Del Haven119911991
Winslow120022002

Black-crowned Night Heron Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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