BirdAnalyst
Species · Washington · BBS 2026 Release · 1966–2025

Great Horned Owl Population Trend in Washington

All statesBirds of prey

Great Horned Owl in Washington has collapsed: down 75% on the route-weighted index since 1973.

-75%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 →
61Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Great Horned Owl Trends in WashingtonNotable 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 →

Great Horned Owl has collapsed in Washington: down 75% on the route-weighted index since 1973.

Great Horned Owl Population Forecast in Washington

If the recent trend holds, Great Horned Owl in Washington is projected to stay roughly flat through 2030, near 0.04 (95% range 0.00–0.41). A 5-year backtest shows a typical error of ±54.3%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.04Projected 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 →
0.00–0.4195% 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 →
±54.3%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, Great Horned Owl in Washington is projected to stay roughly flat through 2030, near 0.04 (95% range 0.00–0.41). A 5-year backtest shows a typical error of ±54.3%, with 100% of held-out values landing inside the 95% band.19712030
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 →
20260.060.000.43
20270.050.000.42
20280.050.000.42
20290.040.000.41
20300.040.000.41

Great Horned Owl Survey Routes in Washington

Routes recording Great Horned Owl in Washington.
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 →
Ewan720121988
Warm Beach319981979
Vashon Is.320242024
Snowden319721971
Pomeroy320242009
Taholah220031997
Harrington220051972
Camas219921992
Tonasket220051985
Leavenworth220241999
Hartline220231999
Mendota 3220052005
Hanford Site119931988
Twisp120171991
Brewster119981992
Keller119951972
Chewelah120141978
Arid Land Er119891989
Deception119941994
Turnbull Nwr120181993
Moses Lake120091982
Reardan120241976
Bunker Hill119751975
Cougar120191973
Rimrock120241973

Great Horned Owl Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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