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Species · Minnesota · BBS 2025 Release · 1966–2024

American Bittern Population Trend in Minnesota

All statesWetland birds

American Bittern in Minnesota has fallen sharply: down 74% on the route-weighted index since 1969.

-74%Since 1969TrendPercent 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 →
75Routes 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 →
57YearsYears 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 MinnesotaNotable 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 →

American Bittern has fallen sharply in Minnesota: down 74% on the route-weighted index since 1969.

American Bittern Population Forecast in Minnesota

If the recent trend holds, American Bittern in Minnesota is projected to fall about 71% by 2029 — from 0.33 in 2024 to a central estimate of 0.09 (95% range 0.00–0.70). A 5-year backtest shows a typical error of ±53.6%, with 100% of held-out values landing inside the 95% band.

-71%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 →
0.09Projected 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 →
0.00–0.7095% 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 →
±53.6%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 Minnesota is projected to fall about 71% by 2029 — from 0.33 in 2024 to a central estimate of 0.09 (95% range 0.00–0.70). A 5-year backtest shows a typical error of ±53.6%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.150.000.76
20260.140.000.75
20270.120.000.73
20280.110.000.72
20290.090.000.70

American Bittern Survey Routes in Minnesota

Routes recording American Bittern in Minnesota.
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 →
Bemidji1319671967
Chisholm920242023
Bigfork620211999
Greenbush520241993
Sherry Lake420221969
Lake Bronson420111979
Grygla320111979
Nett Lake320182016
Sherburne Nr220241993
Chandler219841969
Courtland219911978
Maynard219691969
Princeton219901969
Chokio220221969
Mille Lacs220151968
Pine River220151969
Tenney219801980
Hovland220191976
Sawbill Lndg220191989
Erie220101979
Chokio North220141993
Bagley219981995
Warroad220161993
Money Creek119851985
Hartland120122012

American Bittern Population Trend in Other States

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

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