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

Common Grackle Population Trend in South Carolina

All statesGeneralists

Common Grackle in South Carolina has collapsed: down 88% on the route-weighted index since 1968.

-88%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 →
51Routes 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 →
59YearsYears 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 Grackle 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 →

Common Grackle has collapsed in South Carolina: down 88% on the route-weighted index since 1968.

Common Grackle Population Forecast in South Carolina

If the recent trend holds, Common Grackle in South Carolina is projected to fall about 100% by 2030 — from 7.1 in 2025 to a central estimate of 0.00 (95% range 0.00–19). A 5-year backtest shows a typical error of ±117.8%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–1995% 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 →
±117.8%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 Grackle in South Carolina is projected to fall about 100% by 2030 — from 7.1 in 2025 to a central estimate of 0.00 (95% range 0.00–19). A 5-year backtest shows a typical error of ±117.8%, 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 →
20260.000.0019
20270.000.0019
20280.000.0019
20290.000.0019
20300.000.0019

Common Grackle Survey Routes in South Carolina

Routes recording Common Grackle 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 →
Johns Isle25319791966
Pendleton12119761966
Boiling Spgs6619791967
Boykin Ml Pd6519681966
Landrum6319921972
Chesnee3720151992
Bishopville3020251970
Dillon2720211970
New Holland2620251967
Little Mtn2619881966
Barton Creek2420221967
Blacksburg2120131998
Coward1920251966
Ward1920252017
Holly Hill1820251972
Owings1820041992
Ridgeway1720212010
Green Sea1620252010
Anderson1420181977
Salem Xrd1220191982
Red Bluff1220251996
Adams Run1020251988
Rome720251967
Nixonville719951987
Kingstree720102010

Common Grackle Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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