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

Ferruginous Hawk Population Trend in Washington

All statesGeneralists

Ferruginous Hawk in Washington has fallen sharply: down 64% on the route-weighted index since 1982.

-64%Since 1982TrendPercent 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 →
13Routes 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 →
34YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Ferruginous Hawk 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 →

Ferruginous Hawk has fallen sharply in Washington: down 64% on the route-weighted index since 1982.

Ferruginous Hawk Population Forecast in Washington

If the recent trend holds, Ferruginous Hawk in Washington is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±38.6%, 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 →
0.00–0.0695% 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 →
±38.6%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, Ferruginous Hawk in Washington is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.06). A 5-year backtest shows a typical error of ±38.6%, with 100% of held-out values landing inside the 95% band.19752029
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 →
20250.020.000.06
20260.010.000.06
20270.010.000.06
20280.010.000.06
20290.010.000.06

Ferruginous Hawk Survey Routes in Washington

Routes recording Ferruginous Hawk 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 →
Hanford Site219961988
Keystone220241998
Hatton119931992
Sulphur120082008
Wilbur120022002
Odessa120222022
Othello119861986
Prescott119971982
Horn Rapids120172005
Mesa119951995
Connell120091975
Blewett Pass120042004
Richland120112006

Ferruginous Hawk Population Trend in Other States

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