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

Hairy Woodpecker Population Trend in California

All statesForest birds

Hairy Woodpecker in California has surged: up 134% on the route-weighted index since 1970.

+134%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 →
169Routes 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 Hairy 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 increasecomputed 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 →

Hairy Woodpecker has surged in California: up 134% on the route-weighted index since 1970.

Hairy Woodpecker Population Forecast in California

If the recent trend holds, Hairy Woodpecker in California is projected to rise about 11% by 2029 — from 1.4 in 2024 to a central estimate of 1.5 (95% range 1.1–1.9). A 5-year backtest shows a typical error of ±28.1%, with 60% of held-out values landing inside the 95% band.

+11%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 →
1.5Projected 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 →
1.1–1.995% 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 →
±28.1%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, Hairy Woodpecker in California is projected to rise about 11% by 2029 — from 1.4 in 2024 to a central estimate of 1.5 (95% range 1.1–1.9). A 5-year backtest shows a typical error of ±28.1%, with 60% 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 →
20251.41.11.8
20261.41.11.8
20271.51.11.8
20281.51.11.8
20291.51.11.9

Hairy Woodpecker Survey Routes in California

Routes recording Hairy 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 →
Shasta Lake1720241974
Fairfax1620241972
Chilcoot1320241998
Fish Rock1120141969
Pollock Pines1120241997
Genesee1020241972
South Fork Mtn920222000
Chester820161997
Crowder Flat720192003
Offield Mtn620141973
Forest Hill620221999
Stonyford620182015
Westville520241971
Redwood N.P. 2520132013
Riverton520231973
Bartle520211972
Hat Creek520181974
Lakeshore520241972
Ship Mtn.520161994
Hackamore520072000
Tionesta520211997
Friday Ridge520241994
Eagle Lake420241969
Point Reyes420231970
Navarro420111976

Hairy Woodpecker Population Trend in Other States

alabamaalaskaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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