BirdAnalyst
Species · South Carolina · BBS 2025 Release · 1966–2024

Great Blue Heron Population Trend in South Carolina

All statesWetland birds

Great Blue Heron in South Carolina has risen sharply: up 57% on the route-weighted index since 1968.

+57%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 →
45Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Great Blue 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 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 →

Great Blue Heron has risen sharply in South Carolina: up 57% on the route-weighted index since 1968.

Great Blue Heron Population Forecast in South Carolina

If the recent trend holds, Great Blue Heron in South Carolina is projected to rise about 66% by 2029 — from 0.38 in 2024 to a central estimate of 0.63 (95% range 0.19–1.1). A 5-year backtest shows a typical error of ±50.3%, with 100% of held-out values landing inside the 95% band.

+66%Change 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 →
0.63Projected 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 →
0.19–1.195% 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 →
±50.3%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, Great Blue Heron in South Carolina is projected to rise about 66% by 2029 — from 0.38 in 2024 to a central estimate of 0.63 (95% range 0.19–1.1). A 5-year backtest shows a typical error of ±50.3%, 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 →
20250.610.171.1
20260.620.171.1
20270.620.181.1
20280.630.181.1
20290.630.191.1

Great Blue Heron Survey Routes in South Carolina

Routes recording Great Blue 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 →
Dillon620211972
Pinewood520171998
Foreston320071971
Bishopville220231987
Sandhills220212003
Walterboro220171971
Kiawah Island220241998
Owings220041992
Nixonville219951990
New Ellenton220232018
Battlecreek220212001
Johns Isle119781966
Jamestown120041968
Hardeeville120231968
Rome120231972
Holly Hill120241972
Coward120231983
New Holland120241971
Wagener120121968
Salem Xrd120131985
Barton Creek120191974
Landrum119861986
Plum Branch120222002
Ward120212017
Campobello120242011

Great Blue Heron Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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