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

California Thrasher In Sierra Nevada

All regionsSierra NevadaGeneralists

California Thrasher in Sierra Nevada has collapsed: down 88% on the route-weighted index since 1973.

-88%Since 1973
13Routes In Region
41Years

Notable Signals

long arc declinecomputed index

California Thrasher has collapsed in Sierra Nevada: down 88% on the route-weighted index since 1973.

Forecast

If the recent trend holds, California Thrasher in Sierra Nevada is projected to fall about 100% by 2029 — from 0.16 in 2024 to a central estimate of 0.00 (95% range 0.00–0.40). A 5-year backtest shows a typical error of ±178.4%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2029
0.00Projected 2029 index
0.00–0.4095% range
±178.4%Backtest error
19712029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.000.000.40
20260.000.000.40
20270.000.000.40
20280.000.000.40
20290.000.000.40

Routes In Sierra Nevada

Routes recording California Thrasher in Sierra Nevada.
Greenhorn MtCALIFORNIA41973
Silver CityCALIFORNIA42013
Kings CanyonCALIFORNIA32024
KernvilleCALIFORNIA32008
Cottage SpgsCALIFORNIA21972
DownievilleCALIFORNIA21984
Forest HillCALIFORNIA22022
WestvilleCALIFORNIA11984
Bass LakeCALIFORNIA12018
Higgins CornCALIFORNIA12007
LakeshoreCALIFORNIA11984
CoultervilleCALIFORNIA12010
WawonaCALIFORNIA12019

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