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

Great Horned Owl Population Trend in Michigan

All statesGeneralists

Great Horned Owl in Michigan has fallen sharply: down 62% on the route-weighted index since 1973.

-62%Since 1973TrendPercent 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 →
42Routes 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 →
46YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Great Horned Owl 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 →

Great Horned Owl has fallen sharply in Michigan: down 62% on the route-weighted index since 1973.

Great Horned Owl Population Forecast in Michigan

If the recent trend holds, Great Horned Owl in Michigan is projected to stay roughly flat through 2027, near 0.00 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±59.8%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2027TrendPercent 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 →
0.00Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0695% 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 →
±59.8%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, Great Horned Owl in Michigan is projected to stay roughly flat through 2027, near 0.00 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±59.8%, with 100% of held-out values landing inside the 95% band.19712027
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 →
20230.010.000.07
20240.010.000.07
20250.010.000.07
20260.000.000.07
20270.000.000.06

Great Horned Owl Survey Routes in Michigan

Routes recording Great Horned Owl 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 →
St Charles519781978
Bear Lake220042004
Maple Rapids219881988
Bootjack120062006
Chippewa Lk.120112011
Belding 2120072007
Gibbs City120022002
Seney Nwr120112011
Allegan Wma120161993
Almena120081995
Scottville120221976
Big Blue Lk119901990
Bravo119951995
Tahquamenon119761976
Gilchrist119911991
Skegemog Pt120031994
Nashville120001975
Coopersville120101995
Belding120021984
Galesburg119981977
Howardsville120222000
Monterey119971986
Remus119981998
Raco120161993
Pickford120131983

Great Horned Owl Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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