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

Common Grackle Population Trend in Michigan

All statesGeneralists

Common Grackle in Michigan has collapsed: down 75% on the route-weighted index since 1968.

-75%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 →
107Routes 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 MichiganNotable 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 Michigan: down 75% on the route-weighted index since 1968.

Common Grackle Population Forecast in Michigan

If the recent trend holds, Common Grackle in Michigan is projected to fall about 86% by 2030 — from 13 in 2025 to a central estimate of 1.8 (95% range 0.00–17). A 5-year backtest shows a typical error of ±56.8%, with 100% of held-out values landing inside the 95% band.

-86%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 →
1.8Projected 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 →
0.00–1795% 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 →
±56.8%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 Michigan is projected to fall about 86% by 2030 — from 13 in 2025 to a central estimate of 1.8 (95% range 0.00–17). A 5-year backtest shows a typical error of ±56.8%, 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 →
20265.60.0021
20274.60.0020
20283.70.0019
20292.70.0018
20301.80.0017

Common Grackle Survey Routes in Michigan

Routes recording Common Grackle in Michigan.
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 →
Pettysville9419791969
S Lyons7719921966
Richmond6720241999
North Branch6419991974
Drayton Plns6419871973
Mayfield5720252000
Walloon Lake 25120242005
Holt4920251969
Skeels4720151966
Adair4419951974
Big Rapids3919901967
Galesburg3920251966
Traverse Cty3619921974
Fowlerville3520191974
Lapeer3520252000
St Charles3320191967
Waldenburg3120171968
Marenisco3020191981
Scottville2620251968
Lawrence2620251969
Bell Oak 22620252016
Sand Lake2520251978
Maple Rapids2420251987
Hartland2220111992
Pickford2120251973

Common Grackle Population Trend in Other States

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

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