BirdAnalyst
Species · BCR 23 · BBS 2025 Release · 1966–2024

Least Bittern In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionWetland birds

Least Bittern in Prairie Hardwood Transition has declined: down 33% on the route-weighted index since 1972.

-33%Since 1972TrendPercent 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 →
25Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
38YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Prairie Hardwood Transition. See the full index history below.

Least Bittern In Prairie Hardwood Transition Population Forecast

If the recent trend holds, Least Bittern in Prairie Hardwood Transition is projected to stay roughly flat through 2024, near 0.01 (95% range 0.00–0.02). A 5-year backtest shows a typical error of ±35.5%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2024TrendPercent 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 →
0.01Projected 2024 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0295% 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 →
±35.5%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 Prairie Hardwood Transition is projected to stay roughly flat through 2024, near 0.01 (95% range 0.00–0.02). A 5-year backtest shows a typical error of ±35.5%, with 100% of held-out values landing inside the 95% band.19702024
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 →
20200.010.000.02
20210.010.000.02
20220.010.000.02
20230.010.000.02
20240.010.000.02

Routes In Prairie Hardwood Transition

Routes recording Least Bittern in Prairie Hardwood Transition.
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 →
Money CreekMINNESOTA21989
UnityWISCONSIN22009
NashvilleMICHIGAN11998
CoopersvilleMICHIGAN12004
GalesburgMICHIGAN11980
MontereyMICHIGAN11995
PettysvilleMICHIGAN11976
Chippewa Lk.MICHIGAN12006
OsseoMINNESOTA11979
St StephenMINNESOTA12002
GlenwoodMINNESOTA11993
Sherburne NrMINNESOTA12017
HudsonWISCONSIN12014
DresserWISCONSIN11970
LoraineWISCONSIN12003
MerrillWISCONSIN11997
CochraneWISCONSIN12010
MatherWISCONSIN11986
OmroWISCONSIN11983
Fall RiverWISCONSIN11994
Beaver DamWISCONSIN12013
Mount HorebWISCONSIN11971
StetsonvilleWISCONSIN12019
Buena VistaWISCONSIN12000
BriggsvilleWISCONSIN12017

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