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

Anhinga Population Trend in South Carolina

All statesWetland birds

Anhinga in South Carolina has surged: up 147% on the route-weighted index since 1976.

+147%Since 1976TrendPercent 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 →
16Routes 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 →
32YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Anhinga 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 →

Anhinga has surged in South Carolina: up 147% on the route-weighted index since 1976.

Anhinga Population Forecast in South Carolina

If the recent trend holds, Anhinga in South Carolina is projected to stay roughly flat through 2030, near 0.27 (95% range 0.00–0.55). A 5-year backtest shows a typical error of ±51.6%, with 100% of held-out values landing inside the 95% band.

-7%Change 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 →
0.27Projected 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 →
0.00–0.5595% 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 →
±51.6%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, Anhinga in South Carolina is projected to stay roughly flat through 2030, near 0.27 (95% range 0.00–0.55). A 5-year backtest shows a typical error of ±51.6%, with 100% of held-out values landing inside the 95% band.19732030
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 →
20260.250.000.54
20270.260.000.54
20280.260.000.55
20290.260.000.55
20300.270.000.55

Anhinga Survey Routes in South Carolina

Routes recording Anhinga 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 →
Bennettsville2120171999
Nixville320092009
Kiawah Island320252000
Walterboro219751975
Ward220252025
Jamestown120042004
Hardeeville120231973
Rome120231980
Holly Hill120251988
Coward120252025
Adams Run120231996
Red Bluff120232018
Bishopville120232007
Olar120182018
Pinewood120171998
Dale120251998

Anhinga Population Trend in Other States

alabamaarkansasfloridageorgialouisianamississippinorth-carolinaoklahomatexasvirginia

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