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

Common Grackle Population Trend in Michigan

All statesGeneralists

Common Grackle in Michigan has collapsed: down 76% on the route-weighted index since 1968.

-76%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 →
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 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 76% 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 2029 — from 16 in 2024 to a central estimate of 2.2 (95% range 0.00–18). A 5-year backtest shows a typical error of ±54%, with 100% of held-out values landing inside the 95% band.

-86%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 →
2.2Projected 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 →
0.00–1895% 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 →
±54%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 2029 — from 16 in 2024 to a central estimate of 2.2 (95% range 0.00–18). A 5-year backtest shows a typical error of ±54%, 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 →
20256.10.0022
20265.10.0021
20274.10.0020
20283.20.0019
20292.20.0018

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
Lawrence6520241969
North Branch6419991974
Drayton Plns6419871973
Brocky Lake5320241980
Walloon Lake 25120242005
Skeels4720151966
Maple Rapids4720231987
Lapeer4720242000
Adair4419951974
Big Rapids3919901967
Holt3720241969
Traverse Cty3619921974
Galesburg3520241966
Fowlerville3520191974
St Charles3320191967
Bell Oak 23320232016
Waldenburg3120171968
Marenisco3020191981
Ola3020241974
Coopersville2720241979
Mayfield2520222000
Hartland2220111992

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 2026-05-22.