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Species · Arizona · BBS 2025 Release · 1966–2024

Acorn Woodpecker Population Trend in Arizona

All statesForest birds

Acorn Woodpecker in Arizona has surged: up 119% on the route-weighted index since 1970.

+119%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 →
26Routes 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 Acorn Woodpecker Trends in ArizonaNotable 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 Arizona: up 119% on the route-weighted index since 1970.

Acorn Woodpecker Population Forecast in Arizona

If the recent trend holds, Acorn Woodpecker in Arizona is projected to rise about 22% by 2029 — from 2.3 in 2024 to a central estimate of 2.7 (95% range 0.00–6.3). A 5-year backtest shows a typical error of ±17.6%, with 100% of held-out values landing inside the 95% band.

+22%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 →
2.7Projected 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 →
0.00–6.395% 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 →
±17.6%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 Arizona is projected to rise about 22% by 2029 — from 2.3 in 2024 to a central estimate of 2.7 (95% range 0.00–6.3). A 5-year backtest shows a typical error of ±17.6%, 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 →
20252.80.006.4
20262.80.006.4
20272.80.006.3
20282.80.006.3
20292.70.006.3

Acorn Woodpecker Survey Routes in Arizona

Routes recording Acorn Woodpecker in Arizona.
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 →
Tonto Vill.4120211992
Prescott4020221974
Happy Jack2120241977
Portal1820241975
Patagonia1420241968
Alpine920231992
Mormon Lake819741968
Pinetop820221993
Forest Lakes720241993
Sunizona 2720242001
Sprucedale720231996
Carr Mtn620241985
Peña Blanca520241975
Mt. Graham520232000
Sawmill420141988
Sunizona419971969
Rucker320091993
Tsaile320191993
Aztec Peak219781974
Dragoon120091993
Flagstaff120162009
Zeniff119721972
Blue119901974
Pomerene119801980
Williams120191999

Acorn Woodpecker Population Trend in Other States

californianew-mexicooregontexas

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