BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Black-crowned Night Heron In Great Basin

All regionsGreat BasinWetland birds

Black-crowned Night Heron in Great Basin has surged: up 80% on the route-weighted index since 1971.

+80%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 →
76Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 surged in Great Basin: up 80% on the route-weighted index since 1971.

Black-crowned Night Heron In Great Basin Population Forecast

If the recent trend holds, Black-crowned Night Heron in Great Basin is projected to stay roughly flat through 2029, near 0.22 (95% range 0.00–0.62). A 5-year backtest shows a typical error of ±294.7%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.22Projected 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 →
0.00–0.6295% 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 →
±294.7%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 Great Basin is projected to stay roughly flat through 2029, near 0.22 (95% range 0.00–0.62). A 5-year backtest shows a typical error of ±294.7%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.240.000.64
20260.230.000.64
20270.230.000.63
20280.220.000.63
20290.220.000.62

Routes In Great Basin

Routes recording Black-crowned Night Heron in Great Basin.
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 →
DorrisCALIFORNIA392019
Bear RiverUTAH82023
Oak CityUTAH72011
BrewsterWASHINGTON71986
EurekaNEVADA61998
Honey LakeCALIFORNIA52019
KeystoneWASHINGTON42022
PotholesWASHINGTON42019
Iron GateCALIFORNIA32017
TriangleIDAHO32021
Fish LakeOREGON32018
MacdoelCALIFORNIA22018
Majors PlaceNEVADA22010
Ruby ValleyNEVADA21999
Barnes ValOREGON21972
PrincetonOREGON21985
UmatillaOREGON22021
DeltaUTAH22006
PrescottWASHINGTON22010
NubieberCALIFORNIA12016
RavendaleCALIFORNIA11995
LikelyCALIFORNIA12011
Crowley LakeCALIFORNIA12023
Davis CreekCALIFORNIA12021
Clear Lk ResCALIFORNIA11999

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