BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Pygmy Nuthatch In Coastal California

All regionsCoastal CaliforniaForest birds

Pygmy Nuthatch in Coastal California has fallen sharply: down 66% on the route-weighted index since 1970.

-66%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 →
29Routes In RegionSurvey 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 SignalsNotable 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 declinecomputed 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 fallen sharply in Coastal California: down 66% on the route-weighted index since 1970.

Pygmy Nuthatch In Coastal California Population Forecast

If the recent trend holds, Pygmy Nuthatch in Coastal California is projected to rise about 56% by 2029 — from 0.53 in 2024 to a central estimate of 0.83 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±90%, with 100% of held-out values landing inside the 95% band.

+56%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 →
0.83Projected 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 →
0.00–2.795% 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 →
±90%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 Coastal California is projected to rise about 56% by 2029 — from 0.53 in 2024 to a central estimate of 0.83 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±90%, 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 →
20250.940.002.8
20260.910.002.8
20270.880.002.8
20280.860.002.8
20290.830.002.7

Routes In Coastal California

Routes recording Pygmy Nuthatch in Coastal 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 →
ValyermoCALIFORNIA452018
Mt LagunaCALIFORNIA411987
Big BearCALIFORNIA371986
Mt PinosCALIFORNIA162004
Lake HemetCALIFORNIA151986
Lake Hemet 2CALIFORNIA92023
Lockwood ValCALIFORNIA61987
Waterman GapCALIFORNIA62024
Cleveland NfCALIFORNIA62018
FairfaxCALIFORNIA52024
Green ValleyCALIFORNIA52023
TehamaCALIFORNIA51992
WoodlandsCALIFORNIA52024
Point ReyesCALIFORNIA42021
Anza 2CALIFORNIA42024
CalpellaCALIFORNIA31980
ColmaCALIFORNIA31972
Mt Pinos 2CALIFORNIA32024
Glen EllenCALIFORNIA32001
Cleveland Nf 2CALIFORNIA32022
TujungaCALIFORNIA21971
FallsvaleCALIFORNIA21975
Glen Ellen 2CALIFORNIA22015
PescaderoCALIFORNIA22024
MoragaCALIFORNIA12018

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