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Species · Oregon · BBS 2025 Release · 1966–2024

Acorn Woodpecker Population Trend in Oregon

All statesForest birds

Acorn Woodpecker in Oregon has risen sharply: up 60% on the route-weighted index since 1970.

+60%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 →
17Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Acorn Woodpecker Trends in OregonNotable 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 risen sharply in Oregon: up 60% on the route-weighted index since 1970.

Acorn Woodpecker Population Forecast in Oregon

If the recent trend holds, Acorn Woodpecker in Oregon is projected to fall about 33% by 2029 — from 1.1 in 2024 to a central estimate of 0.72 (95% range 0.11–1.3). A 5-year backtest shows a typical error of ±57.1%, with 20% of held-out values landing inside the 95% band.

-33%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 →
0.72Projected 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 →
0.11–1.395% 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 →
±57.1%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, Acorn Woodpecker in Oregon is projected to fall about 33% by 2029 — from 1.1 in 2024 to a central estimate of 0.72 (95% range 0.11–1.3). A 5-year backtest shows a typical error of ±57.1%, with 20% 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 →
20250.700.081.3
20260.700.091.3
20270.710.101.3
20280.720.101.3
20290.720.111.3

Acorn Woodpecker Survey Routes in Oregon

Routes recording Acorn Woodpecker in Oregon.
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 →
Emigrant Lake 22620242002
Sams Valley2320241993
Emigrant Lk1520011972
Umpqua1320241968
Derby1219931968
Green1020242019
Selma920241993
Secret Val720221977
Adair420241973
Ruch420231992
Dayton420241973
Elkton420241978
Mcminnville320242004
Hazel Camp320221975
Prospect220241993
Days Creek220241974
Canby120241995

Acorn Woodpecker Population Trend in Other States

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