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Species · California · BBS 2025 Release · 1966–2024

Crissal Thrasher Population Trend in California

All statesGeneralists

Crissal Thrasher in California has held roughly steady: up 0% on the route-weighted index since 1975.

+0%Since 1975TrendPercent 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 →
11Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
31YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Crissal Thrasher Trends in CaliforniaNotable 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 Crissal Thrasher in California. See the full index history below.

Crissal Thrasher Population Forecast in California

If the recent trend holds, Crissal Thrasher in California is projected to stay roughly flat through 2024, near 0.01 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±73.6%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2024TrendPercent 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 →
0.01Projected 2024 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0395% 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 →
±73.6%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, Crissal Thrasher in California is projected to stay roughly flat through 2024, near 0.01 (95% range 0.00–0.03). A 5-year backtest shows a typical error of ±73.6%, with 100% of held-out values landing inside the 95% band.19722024
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 →
20200.010.000.03
20210.010.000.03
20220.010.000.03
20230.010.000.03
20240.010.000.03

Crissal Thrasher Survey Routes in California

Routes recording Crissal Thrasher in California.
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 →
Cottonwood319801980
Glamis219951995
Ivanpah220191988
Tecopa119971979
Joshua Tree119941991
Valley Wells120061993
Palo Verde120111973
Brawley119751972
Blythe119731973
Alamo River119941973
Imperial Dam120101979

Crissal Thrasher Population Trend in Other States

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