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

American Bittern Population Trend in Oregon

All statesWetland birds

American Bittern in Oregon has fallen sharply: down 61% on the route-weighted index since 1973.

-61%Since 1973TrendPercent 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 →
22Routes 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 →
47YearsYears 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 OregonNotable 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 Oregon: down 61% on the route-weighted index since 1973.

American Bittern Population Forecast in Oregon

If the recent trend holds, American Bittern in Oregon is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±76.3%, 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 →
0.00Projected 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 →
0.00–0.2495% 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 →
±76.3%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 Oregon is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±76.3%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.020.000.25
20260.010.000.25
20270.010.000.24
20280.010.000.24
20290.000.000.24

American Bittern Survey Routes in Oregon

Routes recording American Bittern in Oregon.
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 →
Merrill420131998
Warner Vally419991996
Bly220012001
Tualatin119941994
Nicolai Mtn.119971997
Days Creek120112011
Modoc Point119841970
Alvord Lake119721972
Bly 2120212007
Adair120121997
Dayton119931993
Elk Lake120241976
Silver Creek120182018
Princeton119841975
Fish Lake120241972
Coquille120232023
Harney Lake120021999
Catlow Rim120152015
Crooked Riv.120022002
Sheaville120222012
Chinchalo120221996
Sams Valley119941994

American Bittern Population Trend in Other States

alaskacaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-dakotaohiooklahomapennsylvaniasouth-carolinasouth-dakotatexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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