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

Common Grackle Population Trend in South Dakota

All statesGeneralists

Common Grackle in South Dakota has fallen sharply: down 52% on the route-weighted index since 1969.

-52%Since 1969TrendPercent 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 →
63Routes 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 Common Grackle Trends in South DakotaNotable 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 fallen sharply in South Dakota: down 52% on the route-weighted index since 1969.

Common Grackle Population Forecast in South Dakota

If the recent trend holds, Common Grackle in South Dakota is projected to fall about 30% by 2029 — from 28 in 2024 to a central estimate of 20 (95% range 0.00–65). A 5-year backtest shows a typical error of ±33.1%, with 100% of held-out values landing inside the 95% band.

-30%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 →
20Projected 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 →
0.00–6595% 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 →
±33.1%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, Common Grackle in South Dakota is projected to fall about 30% by 2029 — from 28 in 2024 to a central estimate of 20 (95% range 0.00–65). A 5-year backtest shows a typical error of ±33.1%, with 100% of held-out values landing inside the 95% band.19672029
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 →
2025230.0068
2026220.0067
2027210.0066
2028200.0065
2029200.0065

Common Grackle Survey Routes in South Dakota

Routes recording Common Grackle in South Dakota.
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 →
Conde39219841967
Roswell30020141967
Isabel18120151990
Cedar Pass18020231969
Eagle Butte15820151990
Chamberlain13020111967
Turton12520241985
Ft Thompson12020111967
Gettysburg11520231969
Lane 210920142000
Promise10120151971
Volunteer10120191967
Forbes10020241967
Lane9919991967
Rockyford9520231968
White Lake7120111967
Lennox6920241967
Veblen6920231967
Howard6520241970
Broadland5820171967
Britton5520231967
Crow Creek5220231967
Gorman5220101979
Rosebud4820111967
Lacreek4320231991

Common Grackle Population Trend in Other States

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

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