BirdAnalyst
Species · BCR 5 · BBS 2025 Release · 1966–2024

American Bittern In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestWetland birds

American Bittern in Northern Pacific Rainforest has fallen sharply: down 68% on the route-weighted index since 1976.

-68%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 →
24Routes 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 →
46YearsYears 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 →

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 Northern Pacific Rainforest: down 68% on the route-weighted index since 1976.

American Bittern In Northern Pacific Rainforest Population Forecast

If the recent trend holds, American Bittern in Northern Pacific Rainforest is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±90.7%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.01Projected 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 →
0.00–0.0795% 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 →
±90.7%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 Northern Pacific Rainforest is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±90.7%, with 100% of held-out values landing inside the 95% band.19742029
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 →
20250.020.000.07
20260.020.000.07
20270.010.000.07
20280.010.000.07
20290.010.000.07

Routes In Northern Pacific Rainforest

Routes recording American Bittern in Northern Pacific Rainforest.
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 →
Mendota 2WASHINGTON32000
WhiskeytownCALIFORNIA22005
IssaquahWASHINGTON21986
South ElmaWASHINGTON22005
Stikine RiverALASKA12009
YrekaCALIFORNIA12017
GazelleCALIFORNIA12016
TualatinOREGON11994
Days CreekOREGON12011
AdairOREGON12012
DaytonOREGON11993
Elk LakeOREGON12024
Sams ValleyOREGON11994
Nicolai Mtn.OREGON11997
CoquilleOREGON12023
TaholahWASHINGTON11989
KamilcheWASHINGTON11988
EverettWASHINGTON11998
IlwacoWASHINGTON11990
MendotaWASHINGTON11988
RaymondWASHINGTON11994
MukilteoWASHINGTON11998
CarnationWASHINGTON12018
Mendota 3WASHINGTON12024

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