BirdAnalyst
Species · Indiana · BBS 2025 Release · 1966–2024

Common Grackle Population Trend in Indiana

All statesGeneralists

Common Grackle in Indiana has fallen sharply: down 62% on the route-weighted index since 1968.

-62%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 →
58YearsYears 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 62% 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 stay roughly flat through 2029, near 38 (95% range 0.00–90). A 5-year backtest shows a typical error of ±85.8%, with 100% of held-out values landing inside the 95% band.

+2%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 →
38Projected 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 →
0.00–9095% 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 →
±85.8%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 Indiana is projected to stay roughly flat through 2029, near 38 (95% range 0.00–90). A 5-year backtest shows a typical error of ±85.8%, with 100% of held-out values landing inside the 95% band.19662029
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 →
2025440.0095
2026420.0094
2027410.0092
2028400.0091
2029380.0090

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 →
Milroy41420241966
Plainfield17119991999
Tipton14319921966
Cross Plains13620241999
South Bend12019911966
Witts Station10420242000
Shelbyville9720241983
Hebron8920221966
Scottsburg7820241982
Brookville7720241966
W Lafayette7520241981
Muncie6719971981
Maplewood6620212000
Decatur5920241999
Newberry5920241999
Packertown5820041967
Portage5520042000
Middletown5420241966
Sexton5220241981
Cyprss4720241999
Monticello4220241981
New Brunswick4220242024
Millersburg4120241981
Middlebury3920241989
Kokomo3920241993

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 2026-05-22.