BirdAnalyst
Species · BCR 15 · BBS 2026 Release · 1966–2025

Great Horned Owl In Sierra Nevada

All regionsSierra NevadaBirds of prey

Great Horned Owl in Sierra Nevada has declined: down 41% on the route-weighted index since 1973.

-41%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 →
24Routes 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 →
46YearsYears 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 Great Horned Owl in Sierra Nevada. See the full index history below.

Great Horned Owl In Sierra Nevada Population Forecast

If the recent trend holds, Great Horned Owl in Sierra Nevada is projected to fall about 32% by 2030 — from 0.28 in 2025 to a central estimate of 0.19 (95% range 0.00–0.41). A 5-year backtest shows a typical error of ±70.9%, with 100% of held-out values landing inside the 95% band.

-32%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 →
0.19Projected 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 →
±70.9%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 Sierra Nevada is projected to fall about 32% by 2030 — from 0.28 in 2025 to a central estimate of 0.19 (95% range 0.00–0.41). A 5-year backtest shows a typical error of ±70.9%, 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 →
20260.190.000.41
20270.190.000.41
20280.190.000.41
20290.190.000.41
20300.190.000.41

Routes In Sierra Nevada

Routes recording Great Horned Owl in Sierra Nevada.
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 →
Little TruckeeCALIFORNIA42025
Bass LakeCALIFORNIA32005
Lassen ParkCALIFORNIA21977
WestvilleCALIFORNIA22014
CrestviewCALIFORNIA22021
Eagle LakeCALIFORNIA11996
JohnsvilleCALIFORNIA12019
WoodfordsCALIFORNIA12019
Greenhorn MtCALIFORNIA11996
Silver CityCALIFORNIA11975
Kings CanyonCALIFORNIA11985
SattleyCALIFORNIA12014
GeneseeCALIFORNIA12015
Higgins CornCALIFORNIA12002
DownievilleCALIFORNIA11992
RivertonCALIFORNIA11973
Hat CreekCALIFORNIA11992
Tahoe NfCALIFORNIA11988
CoultervilleCALIFORNIA12019
WawonaCALIFORNIA12025
Pine MountainCALIFORNIA12005
ChilcootCALIFORNIA12024
StrawberryCALIFORNIA12006
Last ChanceCALIFORNIA12019

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