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Species · South Carolina · BBS 2026 Release · 1966–2025

Yellow-crowned Night Heron Population Trend in South Carolina

All statesWetland birds

Yellow-crowned Night Heron in South Carolina has edged down: down 25% on the route-weighted index since 1975.

-25%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 →
12Routes 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 →
27YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Yellow-crowned Night Heron Trends in South CarolinaNotable 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 Yellow-crowned Night Heron in South Carolina. See the full index history below.

Yellow-crowned Night Heron Population Forecast in South Carolina

If the recent trend holds, Yellow-crowned Night Heron in South Carolina is projected to stay roughly flat through 2030, near 0.10 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±65.9%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.10Projected 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 →
0.00–0.2795% 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 →
±65.9%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, Yellow-crowned Night Heron in South Carolina is projected to stay roughly flat through 2030, near 0.10 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±65.9%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.100.000.27
20270.100.000.27
20280.100.000.27
20290.100.000.27
20300.100.000.27

Yellow-crowned Night Heron Survey Routes in South Carolina

Routes recording Yellow-crowned Night Heron in South Carolina.
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 →
Holly Hill220241993
Adams Run220192006
Pinewood220081999
Johns Isle119751966
Jamestown119961988
Hardeeville120241990
Coward120252025
Foreston119911991
Kiawah Island120221999
Dillon120182018
Nixville120032003
Dale120232010

Yellow-crowned Night Heron Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoisindianakansaskentuckylouisianamarylandmississippimissourinew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniatennesseetexasvirginiawest-virginia

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