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

Green Heron Population Trend in Michigan

All statesWetland birds

Green Heron in Michigan has risen sharply: up 52% on the route-weighted index since 1968.

+52%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 →
77Routes 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 Green 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 →

Green Heron has risen sharply in Michigan: up 52% on the route-weighted index since 1968.

Green Heron Population Forecast in Michigan

If the recent trend holds, Green Heron in Michigan is projected to fall about 38% by 2029 — from 0.64 in 2024 to a central estimate of 0.40 (95% range 0.00–0.93). A 5-year backtest shows a typical error of ±40.1%, with 80% of held-out values landing inside the 95% band.

-38%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 →
0.40Projected 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 →
0.00–0.9395% 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 →
±40.1%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, Green Heron in Michigan is projected to fall about 38% by 2029 — from 0.64 in 2024 to a central estimate of 0.40 (95% range 0.00–0.93). A 5-year backtest shows a typical error of ±40.1%, with 80% 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 →
20250.440.000.97
20260.430.000.96
20270.420.000.94
20280.410.000.94
20290.400.000.93

Green Heron Survey Routes in Michigan

Routes recording Green 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 →
Lawrence420241969
Drayton Plns419781973
Remus320241974
Mottville320191968
Holt320081969
Prattville320181967
Owendale319941993
Cohoctah320242021
Mayfield320212007
Lake City220101970
Big Rapids219901972
Nashville220241969
No Bradley220241970
Cathro220151970
Juniata220241966
Rochester220241993
Richmond220242011
Hamburg 2220222014
New Buffalo220121992
Almena220151994
Barry S.G.A. 2220182014
Ontonagon120172017
Marenisco120162005
Ned Lake120211999
Crystal Fls120241979

Green Heron Population Trend in Other States

alabamaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsin

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