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

Pacific Wren In Coastal California

All regionsCoastal CaliforniaForest birds

Pacific Wren in Coastal California has surged: up 15× on the route-weighted index since 1976.

15×Since 1976TrendPercent 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 →
12Routes 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 Coastal California: up 15× on the route-weighted index since 1976.

Forecast

If the recent trend holds, Pacific Wren in Coastal California is projected to rise about 36% by 2029 — from 0.87 in 2024 to a central estimate of 1.2 (95% range 0.53–1.9). A 5-year backtest shows a typical error of ±289%, with 40% of held-out values landing inside the 95% band.

+36%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 →
1.2Projected 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 →
0.53–1.995% 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 →
±289%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 Coastal California is projected to rise about 36% by 2029 — from 0.87 in 2024 to a central estimate of 1.2 (95% range 0.53–1.9). A 5-year backtest shows a typical error of ±289%, with 40% 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 →
20251.10.441.8
20261.10.471.8
20271.10.481.8
20281.20.511.8
20291.20.531.9

Routes In Coastal California

Routes recording Pacific Wren 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 →
PescaderoCALIFORNIA282024
Point ReyesCALIFORNIA122023
Waterman GapCALIFORNIA112024
FairfaxCALIFORNIA22024
Mark WestCALIFORNIA22012
Orange CoveCALIFORNIA11977
TehamaCALIFORNIA12018
MoragaCALIFORNIA12011
Glen EllenCALIFORNIA11981
Glen Ellen 2CALIFORNIA12008
TomheadCALIFORNIA12008
Hough SpringsCALIFORNIA12007

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