BirdAnalyst
Species · BCR 12 · BBS 2026 Release · 1966–2025

American Bittern In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionWetland birds

American Bittern in Boreal Hardwood Transition has edged down: down 20% on the route-weighted index since 1968.

-20%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 →
104Routes 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 →
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 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 American Bittern in Boreal Hardwood Transition. See the full index history below.

American Bittern In Boreal Hardwood Transition Population Forecast

If the recent trend holds, American Bittern in Boreal Hardwood Transition is projected to rise about 15% by 2030 — from 0.41 in 2025 to a central estimate of 0.47 (95% range 0.01–0.93). A 5-year backtest shows a typical error of ±57.2%, with 100% of held-out values landing inside the 95% band.

+15%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 →
0.47Projected 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 →
0.01–0.9395% 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 →
±57.2%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, American Bittern in Boreal Hardwood Transition is projected to rise about 15% by 2030 — from 0.41 in 2025 to a central estimate of 0.47 (95% range 0.01–0.93). A 5-year backtest shows a typical error of ±57.2%, 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 →
20260.480.020.94
20270.480.020.94
20280.480.020.94
20290.470.010.94
20300.470.010.93

Routes In Boreal Hardwood Transition

Routes recording American Bittern in Boreal 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 →
BemidjiMINNESOTA131967
PickfordMICHIGAN112019
ChisholmMINNESOTA92024
BigforkMINNESOTA62021
PhillipsWISCONSIN52022
Crystal FlsMICHIGAN42025
RacoMICHIGAN42025
CromwellMINNESOTA42025
Sherry LakeMINNESOTA42022
CouderayWISCONSIN42017
Nett LakeMINNESOTA32018
ShanagoldenWISCONSIN31994
Land O' Lakes 2WISCONSIN32022
Weirgor SpringsWISCONSIN32017
MareniscoMICHIGAN22016
HermanMICHIGAN22013
CunardMICHIGAN21983
ShingletonMICHIGAN22003
MuskallongeMICHIGAN22014
GilchristMICHIGAN21980
Lake CityMICHIGAN22006
SkeelsMICHIGAN21969
OberlinMICHIGAN21974
CathroMICHIGAN22013
Beaver LakeMICHIGAN21984

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