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

Black-throated Sparrow Population Trend in California

All statesArid-land birds

Black-throated Sparrow in California has fallen sharply: down 59% on the route-weighted index since 1970.

-59%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 →
78Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-throated 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 →

Black-throated Sparrow has fallen sharply in California: down 59% on the route-weighted index since 1970.

Black-throated Sparrow Population Forecast in California

If the recent trend holds, Black-throated Sparrow in California is projected to fall about 21% by 2029 — from 3.4 in 2024 to a central estimate of 2.7 (95% range 0.00–7.2). A 5-year backtest shows a typical error of ±15.3%, with 100% of held-out values landing inside the 95% band.

-21%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 →
2.7Projected 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 →
0.00–7.295% 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 →
±15.3%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, Black-throated Sparrow in California is projected to fall about 21% by 2029 — from 3.4 in 2024 to a central estimate of 2.7 (95% range 0.00–7.2). A 5-year backtest shows a typical error of ±15.3%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20252.90.007.4
20262.90.007.4
20272.80.007.3
20282.80.007.3
20292.70.007.2

Black-throated Sparrow Survey Routes in California

Routes recording Black-throated 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 →
Big Pine8420241968
Willow Spgs7619811968
Barstow6419981968
Cima5820211970
Ivanpah5220191988
Joshua Tree 24920162013
Greenwater V4720241972
Haiwee Res4420051975
Eureka Val4020241973
Flynn4019961988
Valley Wells3320231969
Essex3119961988
Needles3119731973
Lone Pine2820241970
Lane Mtn2719731973
Joshua Tree2520021970
Wildrose2420221977
Anza Borrego2220241968
Benton2020241974
Kelso Valley1820241973
Lucerne Val1720241974
Lenwood1619851973
Goldstone1420091968
Darwin1420121991
Pearblossom1320241970

Black-throated Sparrow Population Trend in Other States

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