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Species · Louisiana · BBS 2025 Release · 1966–2024

Black-crowned Night Heron Population Trend in Louisiana

All statesWetland birds

Black-crowned Night Heron in Louisiana has risen sharply: up 72% on the route-weighted index since 1970.

+72%Since 1970TrendPercent 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 →
49Routes 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 →
51YearsYears 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 LouisianaNotable 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 →

Black-crowned Night Heron has risen sharply in Louisiana: up 72% on the route-weighted index since 1970.

Black-crowned Night Heron Population Forecast in Louisiana

If the recent trend holds, Black-crowned Night Heron in Louisiana is projected to rise about 245% by 2029 — from 0.20 in 2024 to a central estimate of 0.67 (95% range 0.03–1.3). A 5-year backtest shows a typical error of ±130.8%, with 100% of held-out values landing inside the 95% band.

+245%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 →
0.67Projected 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 →
0.03–1.395% 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 →
±130.8%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 Louisiana is projected to rise about 245% by 2029 — from 0.20 in 2024 to a central estimate of 0.67 (95% range 0.03–1.3). A 5-year backtest shows a typical error of ±130.8%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.640.001.3
20260.650.011.3
20270.660.021.3
20280.660.031.3
20290.670.031.3

Black-crowned Night Heron Survey Routes in Louisiana

Routes recording Black-crowned Night Heron in Louisiana.
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 →
River Road3720102009
Woodlawn1020212008
Berwick620181992
Creole519871967
Tensas Nwr420151991
Kaplan420231998
Atchafalaya320221992
Plettenberg319681968
Shaw320231990
Maurice320241988
Frogmore320231999
Morgan City320142011
Ltl Chenier320171995
Morgan City219771976
Gran Chenier219821971
Baton Rouge220231996
Fishville220102010
Larose219901990
Brousville219991999
Richard220241998
Ltl Chenier 2220112010
Sabine Nwr 2220172009
Natchez220042003
Grand Isle220182017
Ville Platte220191992

Black-crowned Night Heron Population Trend in Other States

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

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