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

Great Blue Heron Population Trend in Michigan

All statesWetland birds

Great Blue Heron in Michigan has surged: up 160% on the route-weighted index since 1968.

+160%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 →
95Routes 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 Great Blue Heron 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 increasecomputed 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 Blue Heron has surged in Michigan: up 160% on the route-weighted index since 1968.

Great Blue Heron Population Forecast in Michigan

If the recent trend holds, Great Blue Heron in Michigan is projected to rise about 28% by 2029 — from 0.81 in 2024 to a central estimate of 1.0 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±33.8%, with 100% of held-out values landing inside the 95% band.

+28%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 →
1.0Projected 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 →
0.00–2.195% 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 →
±33.8%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 Blue Heron in Michigan is projected to rise about 28% by 2029 — from 0.81 in 2024 to a central estimate of 1.0 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±33.8%, 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 →
20251.00.002.1
20261.00.002.1
20271.00.002.1
20281.00.002.1
20291.00.002.1

Great Blue Heron Survey Routes in Michigan

Routes recording Great Blue Heron 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 →
Drayton Plns1219871973
Mottville620241968
North Branch519981974
Irons419891973
Tyre419951971
Bell Oak 2420232016
Chippewa Lk.420241992
Bear Lake320221979
Lawrence320211969
Nashville320241969
Monterey320241978
Remus320211974
Holt320241970
Pettysville319791969
Hamburg320001985
Richmond320242000
Herman220151983
Cunard220141973
Big Blue Lk220241984
Gilchrist220161980
Coopersville220241984
Belding220031983
Galesburg220241971
Howardsville220241969
Brush Creek219921975

Great Blue Heron 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.