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Species · Nevada · BBS 2025 Release · 1966–2024

Black-crowned Night Heron Population Trend in Nevada

All statesWetland birds

Black-crowned Night Heron in Nevada has collapsed: down 90% on the route-weighted index since 1982.

-90%Since 1982TrendPercent 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 →
18Routes 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 →
36YearsYears 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 NevadaNotable 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 collapsed in Nevada: down 90% on the route-weighted index since 1982.

Black-crowned Night Heron Population Forecast in Nevada

If the recent trend holds, Black-crowned Night Heron in Nevada is projected to rise about 177% by 2028 — from 0.06 in 2023 to a central estimate of 0.15 (95% range 0.00–0.98). A 5-year backtest shows a typical error of ±229.5%, with 100% of held-out values landing inside the 95% band.

+177%Change by 2028TrendPercent 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 →
0.15Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.9895% 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 →
±229.5%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 Nevada is projected to rise about 177% by 2028 — from 0.06 in 2023 to a central estimate of 0.15 (95% range 0.00–0.98). A 5-year backtest shows a typical error of ±229.5%, with 100% of held-out values landing inside the 95% band.19722028
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 →
20240.180.001.0
20250.170.001.0
20260.170.001.00
20270.160.000.99
20280.150.000.98

Black-crowned Night Heron Survey Routes in Nevada

Routes recording Black-crowned Night Heron in Nevada.
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 →
Eureka619981990
Ruby Valley219991999
Majors Place220101972
Comins Lake120162013
Sand Pass120162001
Chimney Res.120232023
Austin120152010
Cortez120212016
Oreana120022002
Nixon120001992
Ash Meadows120051994
Toiyabe Nf120141989
Ruby Valley 2120102006
Gardnerville120051992
Fallon120221994
Virgin Creek120161997
Dobbin Creek120061981
Meadow Vally120212021

Black-crowned Night Heron Population Trend in Other States

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

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