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

Northern Pygmy-Owl Population Trend in California

All statesGeneralists

Northern Pygmy-Owl in California has declined: down 36% on the route-weighted index since 1970.

-36%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 →
99Routes 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 Northern Pygmy-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 →

No notable trend signals for Northern Pygmy-Owl in California. See the full index history below.

Northern Pygmy-Owl Population Forecast in California

If the recent trend holds, Northern Pygmy-Owl in California is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±312.9%, with 40% of held-out values landing inside the 95% band.

n/aChange 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 →
0.07Projected 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 →
0.00–0.1495% 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 →
±312.9%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, Northern Pygmy-Owl in California is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±312.9%, with 40% 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 →
20250.070.000.14
20260.070.000.14
20270.070.000.14
20280.070.000.14
20290.070.000.14

Northern Pygmy-Owl Survey Routes in California

Routes recording Northern Pygmy-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 →
Bass Lake820172005
Redwood N.P. 2420122012
San Benito Mtn.320052004
Rio Dell219791979
Mesa Grande220021986
Valyermo220121970
Adelaida219771973
Jackson219751975
Downieville220071982
Waterman Gap220131978
Glen Ellen219951972
Cal Hot Spgs220161994
Gazelle220212002
Burnt Ranch220002000
Tomhead220062003
Forest Hill220221998
Hough Springs220042001
Friday Ridge220171999
Nubieber120071997
Crescent Cty119971995
Honeydew119981970
Forest Hill 2120052005
Lassen Park119811980
Eagle Lake120181972
Calpella119811973

Northern Pygmy-Owl Population Trend in Other States

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