BirdAnalyst
Species · BCR 22 · BBS 2025 Release · 1966–2024

Black-crowned Night Heron In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieWetland birds

Black-crowned Night Heron in Eastern Tallgrass Prairie has fallen sharply: down 60% on the route-weighted index since 1968.

-60%Since 1968TrendPercent 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 →
35Routes 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 →
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 SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Black-crowned Night Heron in Eastern Tallgrass Prairie. See the full index history below.

Black-crowned Night Heron In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Black-crowned Night Heron in Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±331%, 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 →
0.01Projected 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 →
0.00–0.0995% 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 →
±331%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 Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±331%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.020.000.09
20260.020.000.09
20270.020.000.09
20280.010.000.09
20290.010.000.09

Routes In Eastern Tallgrass Prairie

Routes recording Black-crowned Night Heron in Eastern Tallgrass Prairie.
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 →
BartonvilleILLINOIS71999
GaryINDIANA61999
JamestownILLINOIS51995
Bluff SpgsILLINOIS41974
New LenoxILLINOIS21988
ColumbiaILLINOIS22000
PortageINDIANA22001
Crown PointINDIANA22000
GalesburgKANSAS21985
WashingtonMISSOURI21968
BarringtonILLINOIS11995
ItascaILLINOIS12024
GeneseoILLINOIS11994
SheffieldILLINOIS11992
WayneILLINOIS12010
SherburnvillILLINOIS12015
Deer CreekILLINOIS11995
AthensvilleILLINOIS11988
BelleviewILLINOIS11982
Mascoutah LkILLINOIS12005
St MorganILLINOIS12008
YorkvilleILLINOIS12016
Cedar ValleyIOWA11985
PrairieburgIOWA12015
Sioux CityIOWA11990

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