BirdAnalyst
Species · BCR 15 · BBS 2026 Release · 1966–2025

Pacific Wren In Sierra Nevada

All regionsSierra NevadaForest birds

Pacific Wren in Sierra Nevada has surged: up 287% on the route-weighted index since 1974.

+287%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 →
19Routes 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 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 →

Pacific Wren has surged in Sierra Nevada: up 287% on the route-weighted index since 1974.

Pacific Wren In Sierra Nevada Population Forecast

If the recent trend holds, Pacific Wren in Sierra Nevada is projected to stay roughly flat through 2030, near 0.93 (95% range 0.48–1.4). A 5-year backtest shows a typical error of ±19.2%, with 100% of held-out values landing inside the 95% band.

-7%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 →
0.93Projected 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 →
0.48–1.495% 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 →
±19.2%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, Pacific Wren in Sierra Nevada is projected to stay roughly flat through 2030, near 0.93 (95% range 0.48–1.4). A 5-year backtest shows a typical error of ±19.2%, with 100% of held-out values landing inside the 95% band.19722030
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 →
20260.880.431.3
20270.900.441.3
20280.910.461.4
20290.920.471.4
20300.930.481.4

Routes In Sierra Nevada

Routes recording Pacific Wren 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 →
PlacervilleCALIFORNIA82025
WestvilleCALIFORNIA32025
JohnsvilleCALIFORNIA22025
Silver CityCALIFORNIA22013
Tuolumne GroveCALIFORNIA22025
DownievilleCALIFORNIA22025
Bass LakeCALIFORNIA12016
LumberyardCALIFORNIA12025
Kings CanyonCALIFORNIA12010
Butte MeadowCALIFORNIA12014
GeneseeCALIFORNIA12019
RivertonCALIFORNIA12021
LakeshoreCALIFORNIA12008
Chaos CraterCALIFORNIA12000
Meadow ValleyCALIFORNIA12024
Forest HillCALIFORNIA12021
Pollock PinesCALIFORNIA12015
WawonaCALIFORNIA12024
StrawberryCALIFORNIA12019

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