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

Rock Wren In Coastal California

All regionsCoastal CaliforniaForest birds

Rock Wren in Coastal California has edged down: down 11% on the route-weighted index since 1970.

-11%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 →
68Routes 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 →

No notable trend signals for Rock Wren in Coastal California. See the full index history below.

Forecast

If the recent trend holds, Rock Wren in Coastal California is projected to fall about 25% by 2029 — from 0.45 in 2024 to a central estimate of 0.34 (95% range 0.00–0.70). A 5-year backtest shows a typical error of ±46.4%, with 100% of held-out values landing inside the 95% band.

-25%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 →
0.34Projected 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 →
0.00–0.7095% 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 →
±46.4%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, Rock Wren in Coastal California is projected to fall about 25% by 2029 — from 0.45 in 2024 to a central estimate of 0.34 (95% range 0.00–0.70). A 5-year backtest shows a typical error of ±46.4%, 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 →
20250.340.000.71
20260.340.000.71
20270.340.000.71
20280.340.000.71
20290.340.000.70

Routes In Coastal California

Routes recording Rock 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 →
Lake Hemet 2CALIFORNIA241994
White RiverCALIFORNIA101992
PenningtonCALIFORNIA41976
MorenoCALIFORNIA42024
Oak GroveCALIFORNIA42024
ValyermoCALIFORNIA42019
Elizabeth LkCALIFORNIA42015
Lake SuccessCALIFORNIA31974
TujungaCALIFORNIA32021
SangerCALIFORNIA32018
Green ValleyCALIFORNIA32019
Carrizo PlnCALIFORNIA32023
Tracy 2CALIFORNIA32024
Yokohl ValCALIFORNIA21993
Mt PinosCALIFORNIA21984
San YsidroCALIFORNIA21991
OnoCALIFORNIA21993
Sawmill MtnCALIFORNIA22022
Mesa GrandeCALIFORNIA22024
Lockwood ValCALIFORNIA22019
AdelaidaCALIFORNIA22015
MaricopaCALIFORNIA22024
Santa Cruz ICALIFORNIA21988
Gold HillCALIFORNIA21988
Yolla BollyCALIFORNIA22024

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