BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

California Scrub-Jay In Sierra Nevada

All regionsSierra NevadaGeneralists

California Scrub-Jay in Sierra Nevada has collapsed: down 80% on the route-weighted index since 1970.

-80%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 →
28Routes 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 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 →

California Scrub-Jay has collapsed in Sierra Nevada: down 80% on the route-weighted index since 1970.

California Scrub-Jay In Sierra Nevada Population Forecast

If the recent trend holds, California Scrub-Jay in Sierra Nevada is projected to rise about 65% by 2029 — from 1.2 in 2024 to a central estimate of 2.0 (95% range 0.00–5.6). A 5-year backtest shows a typical error of ±90.6%, with 100% of held-out values landing inside the 95% band.

+65%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 →
2.0Projected 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 →
0.00–5.695% 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 →
±90.6%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, California Scrub-Jay in Sierra Nevada is projected to rise about 65% by 2029 — from 1.2 in 2024 to a central estimate of 2.0 (95% range 0.00–5.6). A 5-year backtest shows a typical error of ±90.6%, 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 →
20252.20.005.9
20262.20.005.8
20272.10.005.7
20282.10.005.7
20292.00.005.6

Routes In Sierra Nevada

Routes recording California Scrub-Jay 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 →
KernvilleCALIFORNIA442008
Silver CityCALIFORNIA392013
Bass LakeCALIFORNIA332019
CoultervilleCALIFORNIA142019
Higgins CornCALIFORNIA102024
Greenhorn MtCALIFORNIA82008
Tuolumne GroveCALIFORNIA62024
WawonaCALIFORNIA52024
Pine MountainCALIFORNIA42016
Cottage SpgsCALIFORNIA31975
Forest HillCALIFORNIA32022
Lassen ParkCALIFORNIA21988
WoodfordsCALIFORNIA22021
Kings CanyonCALIFORNIA22024
PlacervilleCALIFORNIA22001
Forest Hill 2CALIFORNIA22005
Eagle LakeCALIFORNIA12021
WestvilleCALIFORNIA11986
SattleyCALIFORNIA12008
Butte MeadowCALIFORNIA11977
GeneseeCALIFORNIA11992
DownievilleCALIFORNIA12017
RivertonCALIFORNIA12018
Hat CreekCALIFORNIA12003
LakeshoreCALIFORNIA12011

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