BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Acorn Woodpecker In Coastal California

All regionsCoastal CaliforniaForest birds

Acorn Woodpecker in Coastal California has surged: up 88% on the route-weighted index since 1970.

+88%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 →
104Routes In RegionSurvey 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 SignalsNotable 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 →

Acorn Woodpecker has surged in Coastal California: up 88% on the route-weighted index since 1970.

Acorn Woodpecker In Coastal California Population Forecast

If the recent trend holds, Acorn Woodpecker in Coastal California is projected to stay roughly flat through 2029, near 27 (95% range 20–35). A 5-year backtest shows a typical error of ±13%, with 100% of held-out values landing inside the 95% band.

+9%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 →
27Projected 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 →
20–3595% 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 →
±13%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, Acorn Woodpecker in Coastal California is projected to stay roughly flat through 2029, near 27 (95% range 20–35). A 5-year backtest shows a typical error of ±13%, 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 →
2025271934
2026272034
2027272034
2028272034
2029272035

Routes In Coastal California

Routes recording Acorn Woodpecker in Coastal 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 →
Mt LagunaCALIFORNIA1111987
Yolla BollyCALIFORNIA902024
Red BluffCALIFORNIA872024
White RiverCALIFORNIA841992
LockwoodCALIFORNIA822024
Yokohl ValCALIFORNIA721997
FairfaxCALIFORNIA652024
Lake BerryessaCALIFORNIA622024
CoalingaCALIFORNIA602022
Orange CoveCALIFORNIA602016
Cal Hot SpgsCALIFORNIA602019
Waterman GapCALIFORNIA562024
TehamaCALIFORNIA522022
Lake HemetCALIFORNIA501986
ParkfieldCALIFORNIA492024
SangerCALIFORNIA482024
Santa YnezCALIFORNIA472019
AdelaidaCALIFORNIA472024
CoyoteCALIFORNIA462024
Cleveland Nf 2CALIFORNIA452022
OnoCALIFORNIA442012
Angelus OaksCALIFORNIA442017
OnealsCALIFORNIA412024
CohassetCALIFORNIA372024
SisquocCALIFORNIA372014

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