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Species · California · BBS 2026 Release · 1966–2025

Red-breasted Nuthatch Population Trend in California

All statesForest birds

Red-breasted Nuthatch in California has surged: up 346% on the route-weighted index since 1970.

+346%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 →
137Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Red-breasted Nuthatch Trends in CaliforniaNotable 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 →

Red-breasted Nuthatch has surged in California: up 346% on the route-weighted index since 1970.

Red-breasted Nuthatch Population Forecast in California

If the recent trend holds, Red-breasted Nuthatch in California is projected to rise about 70% by 2030 — from 3.8 in 2025 to a central estimate of 6.4 (95% range 4.2–8.7). A 5-year backtest shows a typical error of ±59.4%, with 20% of held-out values landing inside the 95% band.

+70%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 →
6.4Projected 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 →
4.2–8.795% 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 →
±59.4%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, Red-breasted Nuthatch in California is projected to rise about 70% by 2030 — from 3.8 in 2025 to a central estimate of 6.4 (95% range 4.2–8.7). A 5-year backtest shows a typical error of ±59.4%, with 20% of held-out values landing inside the 95% band.19682030
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 →
20266.13.88.4
20276.23.98.5
20286.34.08.5
20296.44.18.6
20306.44.28.7

Red-breasted Nuthatch Survey Routes in California

Routes recording Red-breasted Nuthatch in 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 →
Lassen Park4719891972
Riverton4220251973
Goumaz3720111997
Westville3620251971
Pilot Creek3619961994
Medicine Mtn.3520212000
Hat Creek3420181973
South Fork Mtn3420222000
Dirigio3020141999
Little Truckee2820251997
Friday Ridge2820251994
Lumberyard2720251976
Mccloud2720211973
Lake Hemet 22619931992
Meadow Valley2420251999
Strawberry2420191999
Stonyford2420182015
Forest Hill 22320052005
Chester2220171997
Johnsville2120251975
Butte Meadow2120141972
Greenhorn Mt2020081971
Downieville1620251975
Tahoe Nf1619941987
Tionesta1620211997

Red-breasted Nuthatch Population Trend in Other States

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