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

Green Heron Population Trend in South Carolina

All statesWetland birds

Green Heron in South Carolina has fallen sharply: down 56% on the route-weighted index since 1968.

-56%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 →
46Routes 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 →
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 Green 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 →

Green Heron has fallen sharply in South Carolina: down 56% on the route-weighted index since 1968.

Green Heron Population Forecast in South Carolina

If the recent trend holds, Green Heron in South Carolina is projected to fall about 47% by 2029 — from 0.76 in 2024 to a central estimate of 0.40 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±22.1%, with 100% of held-out values landing inside the 95% band.

-47%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 →
0.40Projected 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 →
0.00–1.095% 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 →
±22.1%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, Green Heron in South Carolina is projected to fall about 47% by 2029 — from 0.76 in 2024 to a central estimate of 0.40 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±22.1%, 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 →
20250.450.001.1
20260.440.001.0
20270.420.001.0
20280.410.001.0
20290.400.001.0

Green Heron Survey Routes in South Carolina

Routes recording Green 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 →
Kiawah Island1420241998
Johns Isle419791966
Hardeeville220241971
Dillon220211970
Bishopville220111970
Little Mtn219881966
Plum Branch220171977
Ward220182017
Mount Pisgah220191998
Bennettsville220171998
Carvers Bay219991999
Red Bluff220231996
Jamestown120011969
Rome120211971
Holly Hill120191972
Coward120141972
Foreston120091966
New Holland119851968
Wagener119971967
Boykin Ml Pd119681966
Walterboro119951975
Salem Xrd120051982
Pendleton119701966
Owings120042004
Barton Creek120221969

Green Heron Population Trend in Other States

alabamaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsin

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