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

Tricolored Heron Population Trend in South Carolina

All statesWetland birds

Tricolored Heron in South Carolina has fallen sharply: down 74% on the route-weighted index since 1970.

-74%Since 1970TrendPercent 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 →
6Routes 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 →
33YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Tricolored 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 →

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 →

Tricolored Heron has fallen sharply in South Carolina: down 74% on the route-weighted index since 1970.

Tricolored Heron Population Forecast in South Carolina

If the recent trend holds, Tricolored Heron in South Carolina is projected to stay roughly flat through 2030, near 0.07 (95% range 0.00–0.30). A 5-year backtest shows a typical error of ±55.5%, 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 →
0.07Projected 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 →
0.00–0.3095% 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 →
±55.5%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, Tricolored Heron in South Carolina is projected to stay roughly flat through 2030, near 0.07 (95% range 0.00–0.30). A 5-year backtest shows a typical error of ±55.5%, 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 →
20260.080.000.31
20270.070.000.30
20280.070.000.30
20290.070.000.30
20300.070.000.30

Tricolored Heron Survey Routes in South Carolina

Routes recording Tricolored 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 Hill219801975
Walterboro219751971
Johns Isle119781966
Hardeeville119731968
Kiawah Island120251999
Dale120232005

Tricolored Heron Population Trend in Other States

alabamaarkansasdelawarefloridageorgiakansaslouisianamarylandmississippinew-jerseynorth-carolinatexasvirginia

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