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

Common Gallinule Population Trend in South Carolina

All statesWetland birds

Common Gallinule in South Carolina has surged: up 223% on the route-weighted index since 2002.

+223%Since 2002TrendPercent 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 →
5Routes 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 →
19YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Gallinule 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 Common Gallinule in South Carolina. See the full index history below.

Common Gallinule Population Forecast in South Carolina

If the recent trend holds, Common Gallinule in South Carolina is projected to rise about 75% by 2030 — from 0.11 in 2025 to a central estimate of 0.19 (95% range 0.00–0.46). A 5-year backtest shows a typical error of ±131.5%, with 100% of held-out values landing inside the 95% band.

+75%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 →
0.19Projected 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 →
0.00–0.4695% 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 →
±131.5%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, Common Gallinule in South Carolina is projected to rise about 75% by 2030 — from 0.11 in 2025 to a central estimate of 0.19 (95% range 0.00–0.46). A 5-year backtest shows a typical error of ±131.5%, with 100% of held-out values landing inside the 95% band.19772030
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 →
20260.180.000.46
20270.180.000.46
20280.180.000.46
20290.190.000.46
20300.190.000.46

Common Gallinule Survey Routes in South Carolina

Routes recording Common Gallinule 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 Island220251998
Hardeeville120062006
Walterboro119771977
Bennettsville120022002
Dale120252019

Common Gallinule Population Trend in Other States

alabamaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippinevadanew-jerseynew-yorknorth-carolinaohiopennsylvaniatennesseetexasutahvermontwisconsin

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