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Species · Washington · BBS 2025 Release · 1966–2024

Black-crowned Night Heron Population Trend in Washington

All statesWetland birds

Black-crowned Night Heron in Washington has collapsed: down 95% on the route-weighted index since 1975.

-95%Since 1975TrendPercent 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 →
17Routes 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 →
45YearsYears 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 WashingtonNotable 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 Washington: down 95% on the route-weighted index since 1975.

Black-crowned Night Heron Population Forecast in Washington

If the recent trend holds, Black-crowned Night Heron in Washington is projected to fall about 100% by 2027 — from 0.07 in 2022 to a central estimate of 0.00 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±595.9%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2027TrendPercent 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 →
0.00Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.4495% 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 →
±595.9%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, Black-crowned Night Heron in Washington is projected to fall about 100% by 2027 — from 0.07 in 2022 to a central estimate of 0.00 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±595.9%, with 100% of held-out values landing inside the 95% band.19732027
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 →
20230.000.000.44
20240.000.000.44
20250.000.000.44
20260.000.000.44
20270.000.000.44

Black-crowned Night Heron Survey Routes in Washington

Routes recording Black-crowned Night Heron in Washington.
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 →
Brewster719861986
Keystone420221995
Potholes420191996
Prescott220102010
Hanford Site119961989
Quincy119811981
Wilbur119861986
Othello119871981
Moses Lake120141973
Harrington120042000
Bunker Hill119821982
Mesa119991994
Columbia Nwr120071992
Wapato120221995
Mercer120041992
Scootney Reservoir120102010
Horn Rapids120122006

Black-crowned Night Heron Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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