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Species · BCR 32 · BBS 2026 Release · 1966–2025

LeConte's Thrasher In Coastal California

All regionsCoastal CaliforniaArid-land birds

LeConte's Thrasher in Coastal California has collapsed: down 92% on the route-weighted index since 1970.

-92%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 →
6Routes 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 →
23YearsYears 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 →

LeConte's Thrasher has collapsed in Coastal California: down 92% on the route-weighted index since 1970.

LeConte's Thrasher In Coastal California Population Forecast

If the recent trend holds, LeConte's Thrasher in Coastal California is projected to stay roughly flat through 2030, near 0.00 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±1772.1%, with 40% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–0.3995% 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 →
±1772.1%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, LeConte's Thrasher in Coastal California is projected to stay roughly flat through 2030, near 0.00 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±1772.1%, with 40% 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 →
20260.000.000.39
20270.000.000.39
20280.000.000.39
20290.000.000.39
20300.000.000.39

Routes In Coastal California

Routes recording LeConte's Thrasher in Coastal 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 →
BakersfieldCALIFORNIA41973
Carrizo PlnCALIFORNIA21972
MaricopaCALIFORNIA12025
ShafterCALIFORNIA11989
ArvinCALIFORNIA11972
Buena VistaCALIFORNIA12017

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