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

Verdin Population Trend in California

All statesArid-land birds

Verdin in California has fallen sharply: down 66% on the route-weighted index since 1970.

-66%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 →
35Routes 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 Verdin 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 →

Verdin has fallen sharply in California: down 66% on the route-weighted index since 1970.

Verdin Population Forecast in California

If the recent trend holds, Verdin in California is projected to fall about 19% by 2029 — from 0.28 in 2024 to a central estimate of 0.23 (95% range 0.00–0.59). A 5-year backtest shows a typical error of ±39.7%, with 100% of held-out values landing inside the 95% band.

-19%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 →
0.23Projected 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 →
0.00–0.5995% 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 →
±39.7%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, Verdin in California is projected to fall about 19% by 2029 — from 0.28 in 2024 to a central estimate of 0.23 (95% range 0.00–0.59). A 5-year backtest shows a typical error of ±39.7%, 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 →
20250.250.000.61
20260.240.000.61
20270.240.000.60
20280.230.000.60
20290.230.000.59

Verdin Survey Routes in California

Routes recording Verdin 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 →
Coachella Cn4620131973
Imperial Dam2020101973
Glamis1420181968
Barstow1219981975
Ivanpah820191994
Iron Mtns820182000
Parker Dam720071973
Anza Borrego620241968
Niland620241973
Joshua Tree520021970
Essex519961988
Pearblossom520241970
Palo Verde420241973
Flynn419961988
Tecopa320211979
Lucerne Val320241988
Blythe320031973
Alamo River320181976
Cadiz219881988
Havasu Lake219731973
Joshua Tree 2220162013
Willow Springs 2220242013
Death Valley220031994
Cholla Gard.120211996
Brawley120091972

Verdin Population Trend in Other States

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