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Species · Michigan · BBS 2026 Release · 1966–2025

American Bittern Population Trend in Michigan

All statesWetland birds

American Bittern in Michigan has risen sharply: up 63% on the route-weighted index since 1968.

+63%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 →
61Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable American Bittern 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 →

American Bittern has risen sharply in Michigan: up 63% on the route-weighted index since 1968.

American Bittern Population Forecast in Michigan

If the recent trend holds, American Bittern in Michigan is projected to rise about 11% by 2030 — from 0.32 in 2025 to a central estimate of 0.35 (95% range 0.03–0.68). A 5-year backtest shows a typical error of ±73.6%, with 100% of held-out values landing inside the 95% band.

+11%Change by 2030TrendPercent 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 →
0.35Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.03–0.6895% 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 →
±73.6%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, American Bittern in Michigan is projected to rise about 11% by 2030 — from 0.32 in 2025 to a central estimate of 0.35 (95% range 0.03–0.68). A 5-year backtest shows a typical error of ±73.6%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.340.020.67
20270.340.020.67
20280.350.030.67
20290.350.030.67
20300.350.030.68

American Bittern Survey Routes in Michigan

Routes recording American Bittern 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 →
Pickford1120191973
Crystal Fls420251983
Raco420251971
No Bradley420152015
Monterey320232023
Marenisco220161988
Herman220132013
Cunard219831979
Shingleton220031967
Bravo220212021
Muskallonge220141968
Gilchrist219801976
Lake City220061971
Skeels219691967
Oberlin219741973
Cathro220131971
Beaver Lake219841974
Drayton Plns219751974
Hiawatha Nf220252015
Seney Nwr220251992
Ontonagon120172014
Bergland120181982
Bootjack119981969
Ned Lake120251997
Gibbs City120251979

American Bittern Population Trend in Other States

alaskacaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamainemarylandmassachusettsminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.