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Species · Michigan · BBS 2025 Release · 1966–2024

Pied-billed Grebe Population Trend in Michigan

All statesWetland birds

Pied-billed Grebe in Michigan has collapsed: down 93% on the route-weighted index since 1970.

-93%Since 1970TrendPercent 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 →
37Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Pied-billed Grebe 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 →

Pied-billed Grebe has collapsed in Michigan: down 93% on the route-weighted index since 1970.

Pied-billed Grebe Population Forecast in Michigan

If the recent trend holds, Pied-billed Grebe in Michigan is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±41.8%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.03Projected 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 →
0.00–0.2495% 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 →
±41.8%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, Pied-billed Grebe in Michigan is projected to stay roughly flat through 2029, near 0.03 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±41.8%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.040.000.25
20260.030.000.25
20270.030.000.25
20280.030.000.25
20290.030.000.24

Pied-billed Grebe Survey Routes in Michigan

Routes recording Pied-billed Grebe 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 →
Bear Lake1119691969
Holt719811973
Seney Nwr420181992
Pine River320211992
Bergland219931993
Shingleton219901990
Barry S.G.A.220052005
Lawrence220091970
Muskallonge220192015
Howardsville220091982
Riggsville219851985
Hungerford120122010
Bootjack119931993
Ned Lake120181995
Chippewa Lk.120002000
Crystal Fls120172017
Gibbs City119981998
Allegan Wma120111994
Almena120141995
Creighton120061981
Scott'S Marsh120062006
Big Blue Lk120241987
Barry S.G.A. 2120182016
Tahquamenon120021974
Lake City120061972

Pied-billed Grebe Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwisconsinwyoming

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