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Species · Arizona · BBS 2025 Release · 1966–2024

Pygmy Nuthatch Population Trend in Arizona

All statesForest birds

Pygmy Nuthatch in Arizona has risen sharply: up 74% on the route-weighted index since 1970.

+74%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 →
21Routes 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 Pygmy Nuthatch 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 →

Pygmy Nuthatch has risen sharply in Arizona: up 74% on the route-weighted index since 1970.

Pygmy Nuthatch Population Forecast in Arizona

If the recent trend holds, Pygmy Nuthatch in Arizona is projected to rise about 31% by 2029 — from 2.9 in 2024 to a central estimate of 3.7 (95% range 0.79–6.7). A 5-year backtest shows a typical error of ±30.9%, with 100% of held-out values landing inside the 95% band.

+31%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 →
3.7Projected 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 →
0.79–6.795% 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 →
±30.9%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, Pygmy Nuthatch in Arizona is projected to rise about 31% by 2029 — from 2.9 in 2024 to a central estimate of 3.7 (95% range 0.79–6.7). A 5-year backtest shows a typical error of ±30.9%, 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 →
20253.70.726.6
20263.70.746.6
20273.70.756.7
20283.70.776.7
20293.70.796.7

Pygmy Nuthatch Survey Routes in Arizona

Routes recording Pygmy Nuthatch 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 →
Happy Jack6420241977
Williams3020191993
Pinetop2920221993
Mormon Lake2819751968
Sprucedale2820231992
Sawmill2520141988
Forest Lakes2520241992
Tsaile2220231996
Flagstaff2120221988
Tonto Vill.1720211992
Prescott1620221974
Zeniff1419841969
Alpine920231992
Mt. Graham920231995
Dry Park720241992
Blue619911974
Aztec Peak519781974
Portal220241975
Maine220241992
Carr Mtn220191999
Rucker120072006

Pygmy Nuthatch Population Trend in Other States

californiacoloradoidahomontananebraskanew-mexicooregonsouth-dakotautahwashingtonwyoming

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