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

Brewer's Sparrow In Sierra Nevada

All regionsSierra NevadaGeneralists

Brewer's Sparrow in Sierra Nevada has fallen sharply: down 55% on the route-weighted index since 1971.

-55%Since 1971
14Routes In Region
55Years

Notable Signals

long arc declinecomputed index

Brewer's Sparrow has fallen sharply in Sierra Nevada: down 55% on the route-weighted index since 1971.

Forecast

If the recent trend holds, Brewer's Sparrow in Sierra Nevada is projected to rise about 57% by 2029 — from 1.4 in 2024 to a central estimate of 2.2 (95% range 0.00–5.0). A 5-year backtest shows a typical error of ±129.6%, with 100% of held-out values landing inside the 95% band.

+57%Change by 2029
2.2Projected 2029 index
0.00–5.095% range
±129.6%Backtest error
19692029
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
20252.20.005.0
20262.20.005.0
20272.20.005.0
20282.20.005.0
20292.20.005.0

Routes In Sierra Nevada

Routes recording Brewer's Sparrow in Sierra Nevada.
Eagle LakeCALIFORNIA112024
Last ChanceCALIFORNIA102019
SattleyCALIFORNIA82024
Little TruckeeCALIFORNIA62023
Silver CityCALIFORNIA51977
GoumazCALIFORNIA42011
CrestviewCALIFORNIA42024
DardanelleCALIFORNIA32017
Hat CreekCALIFORNIA21992
Pine MountainCALIFORNIA22009
ChilcootCALIFORNIA22024
WestvilleCALIFORNIA11977
JohnsvilleCALIFORNIA12024
WoodfordsCALIFORNIA12024

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