BirdAnalyst
Species · California · BBS 2025 Release · 1966–2024

Sagebrush Sparrow Population Trend in California

All statesGeneralists

Sagebrush Sparrow in California has fallen sharply: down 62% on the route-weighted index since 1974.

-62%Since 1974TrendPercent 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 →
14Routes 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 →
49YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Sagebrush Sparrow 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 →

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 →

Sagebrush Sparrow has fallen sharply in California: down 61% on the route-weighted index since 1974.

Sagebrush Sparrow Population Forecast in California

If the recent trend holds, Sagebrush Sparrow in California is projected to fall about 75% by 2029 — from 0.15 in 2024 to a central estimate of 0.04 (95% range 0.00–0.22). A 5-year backtest shows a typical error of ±64.3%, with 100% of held-out values landing inside the 95% band.

-75%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 →
0.04Projected 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 →
0.00–0.2295% 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 →
±64.3%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, Sagebrush Sparrow in California is projected to fall about 75% by 2029 — from 0.15 in 2024 to a central estimate of 0.04 (95% range 0.00–0.22). A 5-year backtest shows a typical error of ±64.3%, with 100% of held-out values landing inside the 95% band.19722029
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 →
20250.040.000.23
20260.040.000.23
20270.040.000.22
20280.040.000.22
20290.040.000.22

Sagebrush Sparrow Survey Routes in California

Routes recording Sagebrush Sparrow 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 →
Bartle3619771977
Honey Lake1320241972
Ingalls320001985
Macdoel319771977
Mt Shasta319751975
Cedarville320011974
Davis Creek220011977
Dorris219761976
Lassen Park219811981
Ravendale120241974
Clear Lk Res119971974
Tionesta120212012
Likely119791972
Madeline120022002

Sagebrush Sparrow Population Trend in Other States

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