BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Ferruginous Hawk In Great Basin

All regionsGreat BasinGeneralists

Ferruginous Hawk in Great Basin has surged: up 315% on the route-weighted index since 1970.

+315%Since 1970TrendPercent 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 →
118Routes 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 →
56YearsYears 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 increasecomputed 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 surged in Great Basin: up 315% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Ferruginous Hawk in Great Basin is projected to stay roughly flat through 2029, near 0.37 (95% range 0.18–0.55). A 5-year backtest shows a typical error of ±30.5%, with 100% of held-out values landing inside the 95% band.

+3%Change 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 →
0.37Projected 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 →
0.18–0.5595% 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 →
±30.5%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 Great Basin is projected to stay roughly flat through 2029, near 0.37 (95% range 0.18–0.55). A 5-year backtest shows a typical error of ±30.5%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.350.170.53
20260.350.170.54
20270.360.180.54
20280.360.180.54
20290.370.180.55

Routes In Great Basin

Routes recording Ferruginous Hawk in Great Basin.
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 →
DuboisIDAHO92024
SnowvilleUTAH72024
BerylUTAH62024
Silver CityIDAHO42002
Fandango CanOREGON42024
Malheur NwrOREGON42022
Pine CreekUTAH42018
Cedar HillIDAHO32014
Lost RiverIDAHO32024
ImnahaOREGON31982
BlitzenOREGON31993
Salt SpringsUTAH32019
Grouse CreekUTAH32010
RavendaleCALIFORNIA22008
AcequiaIDAHO22012
Mud LakeIDAHO22021
AlmoIDAHO22021
Kyle CanyonIDAHO22024
Circular BuIDAHO22024
CortezNEVADA22024
WillisNEVADA22015
Ruby ValleyNEVADA22000
Chimney Res.NEVADA22023
BuchananOREGON22000
JosephOREGON22024

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