BirdAnalyst
Species · California · BBS 2026 Release · 1966–2025

Greater Roadrunner Population Trend in California

All statesArid-land birds

Greater Roadrunner in California has collapsed: down 79% on the route-weighted index since 1970.

-79%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 →
96Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Greater Roadrunner 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 →

Greater Roadrunner has collapsed in California: down 79% on the route-weighted index since 1970.

Greater Roadrunner Population Forecast in California

If the recent trend holds, Greater Roadrunner in California is projected to fall about 91% by 2030 — from 0.13 in 2025 to a central estimate of 0.01 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±94.9%, with 100% of held-out values landing inside the 95% band.

-91%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 →
0.01Projected 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 →
0.00–0.2195% 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 →
±94.9%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, Greater Roadrunner in California is projected to fall about 91% by 2030 — from 0.13 in 2025 to a central estimate of 0.01 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±94.9%, 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 →
20260.030.000.22
20270.020.000.22
20280.020.000.22
20290.020.000.21
20300.010.000.21

Greater Roadrunner Survey Routes in California

Routes recording Greater Roadrunner 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 →
Cima620211970
Anza Borrego420251968
Alamo River319941973
Jacumba320251974
Brawley320101971
Buena Vista320171990
Ubehebe219871987
Mt Pinos219941985
Inyokern220241989
Ivanpah219941989
Big Bear219811981
Essex219941989
Blythe220031976
Maricopa219931970
Sanger220212021
Kelso Valley220221974
Red Bluff119791978
Tres Pinos120032003
Oilfields119991999
Gravesboro119741974
Wildrose119791978
Parkfield120222022
Bakersfield119971968
Onyx120011968
Calif City120151978

Greater Roadrunner Population Trend in Other States

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