BirdAnalyst
Species · BCR 9 · BBS 2026 Release · 1966–2025

Northern Harrier In Great Basin

All regionsGreat BasinBirds of prey

Northern Harrier in Great Basin has increased: up 26% on the route-weighted index since 1970.

+26%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 →
217Routes 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 →
57YearsYears 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 →

No notable trend signals for Northern Harrier in Great Basin. See the full index history below.

Northern Harrier In Great Basin Population Forecast

If the recent trend holds, Northern Harrier in Great Basin is projected to stay roughly flat through 2030, near 0.97 (95% range 0.41–1.5). A 5-year backtest shows a typical error of ±47.8%, with 100% of held-out values landing inside the 95% band.

+3%Change 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 →
0.97Projected 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 →
0.41–1.595% 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 →
±47.8%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, Northern Harrier in Great Basin is projected to stay roughly flat through 2030, near 0.97 (95% range 0.41–1.5). A 5-year backtest shows a typical error of ±47.8%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.970.411.5
20270.970.411.5
20280.970.411.5
20290.970.411.5
20300.970.411.5

Routes In Great Basin

Routes recording Northern Harrier 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 →
SnowvilleUTAH142025
HikoNEVADA92016
DorrisCALIFORNIA82019
Walla WallaWASHINGTON81993
Ruby Valley 2NEVADA72024
Battle MtnOREGON72025
Bowden HillsOREGON72025
PrincetonOREGON61985
PomonaWASHINGTON61999
Daniels ResIDAHO52025
PendletonOREGON52024
WilburWASHINGTON52021
Davis CreekCALIFORNIA41998
LeadoreIDAHO42024
Glenns FerryIDAHO41986
Circular BuIDAHO42025
Harney LakeOREGON42024
Warner VallyOREGON42024
Flook LakeOREGON42025
Johnson CanUTAH42024
Bear RiverUTAH42025
Peplin MountainUTAH42025
EwanWASHINGTON42019
PotholesWASHINGTON42019
IngallsCALIFORNIA32000

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