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

Least Bittern Population Trend in Minnesota

All statesWetland birds

Least Bittern in Minnesota has declined: down 35% on the route-weighted index since 1976.

-35%Since 1976TrendPercent 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 →
14Routes 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 →
24YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Least 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 →

No notable trend signals for Least Bittern in Minnesota. See the full index history below.

Least Bittern Population Forecast in Minnesota

If the recent trend holds, Least Bittern in Minnesota is projected to fall about 71% by 2027 — from 0.06 in 2022 to a central estimate of 0.02 (95% range 0.00–0.05). A 5-year backtest shows a typical error of ±51.2%, with 80% of held-out values landing inside the 95% band.

-71%Change 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 →
0.02Projected 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 →
0.00–0.0595% 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 →
±51.2%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, Least Bittern in Minnesota is projected to fall about 71% by 2027 — from 0.06 in 2022 to a central estimate of 0.02 (95% range 0.00–0.05). A 5-year backtest shows a typical error of ±51.2%, with 80% of held-out values landing inside the 95% band.19722027
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 →
20230.020.000.05
20240.020.000.05
20250.020.000.05
20260.020.000.05
20270.020.000.05

Least Bittern Survey Routes in Minnesota

Routes recording Least 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 →
Fairmont320222022
Money Creek219891972
Bemidji219791979
Big Stone220092005
Glenwood119931993
Sherburne Nr120171991
Ash Creek119751975
Courtland120162016
Dawson120042004
Osseo119791979
St Stephen120022001
Appleton119821982
Greenbush120162016
Wigwam Bay120142014

Least Bittern Population Trend in Other States

alabamaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaslouisianamarylandmichiganmississippimissourinebraskanevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooregonsouth-carolinasouth-dakotatexasvermontvirginiawisconsin

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