BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Northern Pygmy-Owl In Sierra Nevada

All regionsSierra NevadaGeneralists

Northern Pygmy-Owl in Sierra Nevada has fallen sharply: down 74% on the route-weighted index since 1972.

-74%Since 1972TrendPercent 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 →
33Routes 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 →
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 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 →

Northern Pygmy-Owl has fallen sharply in Sierra Nevada: down 74% on the route-weighted index since 1972.

Northern Pygmy-Owl In Sierra Nevada Population Forecast

If the recent trend holds, Northern Pygmy-Owl in Sierra Nevada is projected to rise about 72% by 2029 — from 0.05 in 2024 to a central estimate of 0.09 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±120.3%, with 100% of held-out values landing inside the 95% band.

+72%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 →
0.09Projected 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 →
0.00–0.4295% 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 →
±120.3%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, Northern Pygmy-Owl in Sierra Nevada is projected to rise about 72% by 2029 — from 0.05 in 2024 to a central estimate of 0.09 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±120.3%, 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 →
20250.100.000.44
20260.100.000.43
20270.100.000.43
20280.100.000.43
20290.090.000.42

Routes In Sierra Nevada

Routes recording Northern Pygmy-Owl in Sierra Nevada.
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 →
Bass LakeCALIFORNIA82017
DownievilleCALIFORNIA22007
Forest HillCALIFORNIA22022
Lassen ParkCALIFORNIA11981
Eagle LakeCALIFORNIA12018
WestvilleCALIFORNIA12012
Cottage SpgsCALIFORNIA11968
DardanelleCALIFORNIA12015
JohnsvilleCALIFORNIA12017
WoodfordsCALIFORNIA12014
LumberyardCALIFORNIA12014
Greenhorn MtCALIFORNIA11997
Silver CityCALIFORNIA12009
Kings CanyonCALIFORNIA11983
Tuolumne GroveCALIFORNIA11999
Butte MeadowCALIFORNIA11996
GeneseeCALIFORNIA12018
RivertonCALIFORNIA12023
Hat CreekCALIFORNIA12015
LakeshoreCALIFORNIA12001
Chaos CraterCALIFORNIA12016
PaxtonCALIFORNIA12009
Meadow ValleyCALIFORNIA12012
Little TruckeeCALIFORNIA12017
Pollock PinesCALIFORNIA12024

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