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

Pacific Wren In Sierra Nevada

All regionsSierra NevadaForest birds

Pacific Wren in Sierra Nevada has surged: up 266% on the route-weighted index since 1974.

+266%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 →
49YearsYears 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 266% on the route-weighted index since 1974.

Forecast

If the recent trend holds, Pacific Wren in Sierra Nevada is projected to rise about 15% by 2029 — from 0.79 in 2024 to a central estimate of 0.91 (95% range 0.45–1.4). A 5-year backtest shows a typical error of ±19.4%, with 100% of held-out values landing inside the 95% band.

+15%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 →
0.91Projected 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 →
0.45–1.495% 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 →
±19.4%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, Pacific Wren in Sierra Nevada is projected to rise about 15% by 2029 — from 0.79 in 2024 to a central estimate of 0.91 (95% range 0.45–1.4). A 5-year backtest shows a typical error of ±19.4%, with 100% of held-out values landing inside the 95% band.19722029
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 →
20250.860.401.3
20260.870.421.3
20270.880.431.3
20280.900.441.4
20290.910.451.4

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 →
LumberyardCALIFORNIA42024
WestvilleCALIFORNIA32024
Tuolumne GroveCALIFORNIA32018
PlacervilleCALIFORNIA32024
Silver CityCALIFORNIA22013
DownievilleCALIFORNIA22024
Bass LakeCALIFORNIA12016
JohnsvilleCALIFORNIA12024
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 2026-05-22.