BirdAnalyst
Species · Indiana · BBS 2026 Release · 1966–2025

Common Grackle Population Trend in Indiana

All statesGeneralists

Common Grackle in Indiana has fallen sharply: down 60% on the route-weighted index since 1968.

-60%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 →
69Routes 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 IndianaNotable 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 Indiana: down 60% on the route-weighted index since 1968.

Common Grackle Population Forecast in Indiana

If the recent trend holds, Common Grackle in Indiana is projected to rise about 12% by 2030 — from 32 in 2025 to a central estimate of 36 (95% range 0.00–87). A 5-year backtest shows a typical error of ±76.1%, with 100% of held-out values landing inside the 95% band.

+12%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 →
36Projected 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 →
0.00–8795% 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 →
±76.1%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 Indiana is projected to rise about 12% by 2030 — from 32 in 2025 to a central estimate of 36 (95% range 0.00–87). A 5-year backtest shows a typical error of ±76.1%, 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 →
2026420.0093
2027400.0091
2028390.0090
2029370.0088
2030360.0087

Common Grackle Survey Routes in Indiana

Routes recording Common Grackle in Indiana.
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 →
Brookville18420251966
Plainfield17119991999
Tipton14319921966
Decatur12120251999
South Bend12019911966
Milroy11320251966
Scottsburg9820251982
Rensselaer9120251999
Witts Station8520252000
Muncie6719971981
Maplewood6620212000
Newberry6420251999
Packertown5820041967
Portage5520042000
Sexton5220241981
Vevay4820251966
Knox4720251981
Millersburg4120241981
Hebron3920251966
Kokomo3920241993
Fowler3820241966
Jamestown3820251986
Laporte3620241999
W Lafayette3520251981
Portage 23420252005

Common Grackle Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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