BirdAnalyst
Species · BCR 33 · BBS 2025 Release · 1966–2024

California Scrub-Jay In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsGeneralists

California Scrub-Jay in Sonoran and Mojave Deserts has risen sharply: up 66% on the route-weighted index since 1970.

+66%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 →
9Routes 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 →

California Scrub-Jay has risen sharply in Sonoran and Mojave Deserts: up 66% on the route-weighted index since 1970.

California Scrub-Jay In Sonoran and Mojave Deserts Population Forecast

If the recent trend holds, California Scrub-Jay in Sonoran and Mojave Deserts is projected to rise about 65% by 2029 — from 0.67 in 2024 to a central estimate of 1.1 (95% range 0.15–2.1). A 5-year backtest shows a typical error of ±88%, 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 →
1.1Projected 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 →
0.15–2.195% 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 →
±88%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 Sonoran and Mojave Deserts is projected to rise about 65% by 2029 — from 0.67 in 2024 to a central estimate of 1.1 (95% range 0.15–2.1). A 5-year backtest shows a typical error of ±88%, 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 →
20251.10.132.0
20261.10.142.0
20271.10.142.0
20281.10.142.1
20291.10.152.1

Routes In Sonoran and Mojave Deserts

Routes recording California Scrub-Jay in Sonoran and Mojave Deserts.
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 →
OnyxCALIFORNIA272015
Kelso ValleyCALIFORNIA132024
PearblossomCALIFORNIA62024
Joshua TreeCALIFORNIA42002
Joshua Tree 2CALIFORNIA22016
Willow SpgsCALIFORNIA11971
BarstowCALIFORNIA11998
Anza BorregoCALIFORNIA12024
Cholla Gard.CALIFORNIA12021

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