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

Lewis's Woodpecker Population Trend in California

All statesForest birds

Lewis's Woodpecker in California has collapsed: down 75% on the route-weighted index since 1970.

-75%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 →
43Routes 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 Lewis's Woodpecker 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 →

Lewis's Woodpecker has collapsed in California: down 75% on the route-weighted index since 1970.

Lewis's Woodpecker Population Forecast in California

If the recent trend holds, Lewis's Woodpecker in California is projected to stay roughly flat through 2029, near 0.09 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±530.2%, with 100% 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 →
0.09Projected 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 →
0.00–0.2195% 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 →
±530.2%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, Lewis's Woodpecker in California is projected to stay roughly flat through 2029, near 0.09 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±530.2%, 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 →
20250.090.000.22
20260.090.000.22
20270.090.000.22
20280.090.000.21
20290.090.000.21

Lewis's Woodpecker Survey Routes in California

Routes recording Lewis's Woodpecker 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 →
Last Chance820002000
Iron Gate620191988
Lockwood419731972
Mt Shasta420191975
Coalinga319761974
Nubieber220001970
Eagle Lake219971969
Fall River Mills220111998
Redding219771976
Hollister219921973
Bartle220041972
Horse Creek120001980
Mt Baldy119971997
Gazelle120101988
Holmes119831983
Creston119851973
Hughson119811981
Tionesta120182004
Likely119841978
Gold Hill120032003
Tres Pinos119941973
Crowley Lake120231974
Paxton120212015
Parkfield120131968
Junction Cty119731973

Lewis's Woodpecker Population Trend in Other States

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