BirdAnalyst
Species · BCR 11 · BBS 2026 Release · 1966–2025

Black-crowned Night Heron In Prairie Potholes

All regionsPrairie PotholesWetland birds

Black-crowned Night Heron in Prairie Potholes has collapsed: down 77% on the route-weighted index since 1969.

-77%Since 1969TrendPercent 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 →
60Routes 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 →
58YearsYears 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 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 Prairie Potholes: down 77% on the route-weighted index since 1969.

Black-crowned Night Heron In Prairie Potholes Population Forecast

If the recent trend holds, Black-crowned Night Heron in Prairie Potholes is projected to rise about 101% by 2030 — from 0.18 in 2025 to a central estimate of 0.35 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±95.6%, with 100% of held-out values landing inside the 95% band.

+101%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 →
0.35Projected 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 →
0.00–1.195% 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 →
±95.6%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 Prairie Potholes is projected to rise about 101% by 2030 — from 0.18 in 2025 to a central estimate of 0.35 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±95.6%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20260.380.001.2
20270.370.001.2
20280.370.001.2
20290.360.001.2
20300.350.001.1

Routes In Prairie Potholes

Routes recording Black-crowned Night Heron in Prairie Potholes.
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 →
TrippSOUTH-DAKOTA211999
FormanNORTH-DAKOTA112015
Lakota 2NORTH-DAKOTA112025
HartlandMINNESOTA101967
BuchananNORTH-DAKOTA82024
Lake GeorgeNORTH-DAKOTA62021
TitonkaIOWA51984
DanzigNORTH-DAKOTA52013
BrittonSOUTH-DAKOTA52021
GarnerIOWA41971
LakotaNORTH-DAKOTA42009
BraddockNORTH-DAKOTA42023
White LakeSOUTH-DAKOTA42011
VeblenSOUTH-DAKOTA42008
TenneyMINNESOTA31990
Sheyenne LkNORTH-DAKOTA32022
HowardSOUTH-DAKOTA32004
Crow CreekSOUTH-DAKOTA32022
WilmotSOUTH-DAKOTA31997
ArlingtonMINNESOTA21996
GluekMINNESOTA21984
Big StoneMINNESOTA22008
Ester LakeMONTANA22019
EmeradoNORTH-DAKOTA21976
Horsehead LkNORTH-DAKOTA22024

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