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Species · California · BBS 2026 Release · 1966–2025

Abert's Towhee Population Trend in California

All statesArid-land birds

Abert's Towhee in California has increased: up 48% on the route-weighted index since 1974.

+48%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 →
10Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Abert's Towhee 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 →

No notable trend signals for Abert's Towhee in California. See the full index history below.

Abert's Towhee Population Forecast in California

If the recent trend holds, Abert's Towhee in California is projected to rise about 22% by 2030 — from 0.06 in 2025 to a central estimate of 0.07 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±34.3%, with 100% of held-out values landing inside the 95% band.

+22%Change 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 →
0.07Projected 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 →
0.00–0.1795% 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 →
±34.3%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, Abert's Towhee in California is projected to rise about 22% by 2030 — from 0.06 in 2025 to a central estimate of 0.07 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±34.3%, with 100% 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 →
20260.070.000.17
20270.070.000.17
20280.070.000.17
20290.070.000.17
20300.070.000.17

Abert's Towhee Survey Routes in California

Routes recording Abert's Towhee 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 →
Brawley920011976
Parker Dam620071973
Niland520251979
Coachella Cn420002000
Blythe419791979
Imperial Dam320061973
Glamis220171968
Havasu Lake220031973
Palo Verde120231973
Alamo River119911973

Abert's Towhee Population Trend in Other States

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