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

Burrowing Owl Population Trend in California

All statesGeneralists

Burrowing Owl in California has collapsed: down 85% on the route-weighted index since 1970.

-85%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 →
64Routes 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 Burrowing Owl 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 →

Burrowing Owl has collapsed in California: down 85% on the route-weighted index since 1970.

Burrowing Owl Population Forecast in California

If the recent trend holds, Burrowing Owl in California is projected to rise about 140% by 2029 — from 0.12 in 2024 to a central estimate of 0.28 (95% range 0.00–0.92). A 5-year backtest shows a typical error of ±267%, with 100% of held-out values landing inside the 95% band.

+140%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 →
0.28Projected 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 →
0.00–0.9295% 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 →
±267%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, Burrowing Owl in California is projected to rise about 140% by 2029 — from 0.12 in 2024 to a central estimate of 0.28 (95% range 0.00–0.92). A 5-year backtest shows a typical error of ±267%, 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 →
20250.320.000.95
20260.310.000.94
20270.300.000.94
20280.290.000.93
20290.280.000.92

Burrowing Owl Survey Routes in California

Routes recording Burrowing Owl 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 →
Brawley2920121971
Alamo River2420181973
Mesa Grande1620022002
Oilfields1519811968
Tranquillity1520041972
Niland1120241973
Buena Vista720191990
Hollister620071976
Atwater520071972
Caruthers419861978
Bakersfield420041968
Moreno420121968
Ventucopa319721972
Shafter319891971
Arvin320161971
San Ysidro319761973
Hollister 2320122012
Riovista220181968
Collegeville220041968
Hughson219871981
Goldstone220051987
Palo Verde220221973
Eureka Val219931993
Lenwood219841978
Ravendale219921987

Burrowing Owl Population Trend in Other States

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