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Species · Arizona · BBS 2026 Release · 1966–2025

Clark's Nutcracker Population Trend in Arizona

All statesForest birds

Clark's Nutcracker in Arizona has surged: up 120% on the route-weighted index since 1974.

+120%Since 1974TrendPercent 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 →
14Routes 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 →
50YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Clark's Nutcracker 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 →

Clark's Nutcracker has surged in Arizona: up 120% on the route-weighted index since 1974.

Clark's Nutcracker Population Forecast in Arizona

If the recent trend holds, Clark's Nutcracker in Arizona is projected to fall about 73% by 2030 — from 0.41 in 2025 to a central estimate of 0.11 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±88.7%, with 100% of held-out values landing inside the 95% band.

-73%Change by 2030TrendPercent 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 →
0.11Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.4495% 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 →
±88.7%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, Clark's Nutcracker in Arizona is projected to fall about 73% by 2030 — from 0.41 in 2025 to a central estimate of 0.11 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±88.7%, with 100% of held-out values landing inside the 95% band.19692030
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 →
20260.120.000.45
20270.120.000.44
20280.120.000.44
20290.120.000.44
20300.110.000.44

Clark's Nutcracker Survey Routes in Arizona

Routes recording Clark's Nutcracker 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 →
Sprucedale920251992
Maine719941993
Blue619911974
Portal519971997
Dry Park520251992
Williams320012001
Round Rock219701970
Flagstaff220251988
Sawmill220101988
House Rock120182008
Forest Lakes119951995
Alpine120251992
Tsaile120231995
Mormon Lake119691969

Clark's Nutcracker Population Trend in Other States

californiacoloradoidahomontananevadanew-mexicooregonsouth-dakotautahwashingtonwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.