BirdAnalyst
Species · BCR 32 · BBS 2026 Release · 1966–2025

Vaux's Swift In Coastal California

All regionsCoastal CaliforniaAerial insectivores

Vaux's Swift in Coastal California has held roughly steady: down 7% on the route-weighted index since 1977.

-7%Since 1977TrendPercent 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 →
39YearsYears 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 Vaux's Swift in Coastal California. See the full index history below.

Vaux's Swift In Coastal California Population Forecast

If the recent trend holds, Vaux's Swift in Coastal California is projected to rise about 34% by 2030 — from 0.08 in 2025 to a central estimate of 0.11 (95% range 0.00–0.23). A 5-year backtest shows a typical error of ±198.7%, with 100% of held-out values landing inside the 95% band.

+34%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 →
0.11Projected 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 →
0.00–0.2395% 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 →
±198.7%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, Vaux's Swift in Coastal California is projected to rise about 34% by 2030 — from 0.08 in 2025 to a central estimate of 0.11 (95% range 0.00–0.23). A 5-year backtest shows a typical error of ±198.7%, 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 →
20260.100.000.23
20270.100.000.23
20280.100.000.23
20290.100.000.23
20300.110.000.23

Routes In Coastal California

Routes recording Vaux's Swift 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 →
AdelaidaCALIFORNIA71977
Orange CoveCALIFORNIA62002
CoyoteCALIFORNIA52022
Red BluffCALIFORNIA42011
Lake SuccessCALIFORNIA41978
CopperopolisCALIFORNIA42017
Carmel ValCALIFORNIA22017
Angelus OaksCALIFORNIA21989
Cal Hot SpgsCALIFORNIA22014
Glen Ellen 3CALIFORNIA22025
FairfaxCALIFORNIA11980
OnoCALIFORNIA12011
Mt BaldyCALIFORNIA12015
TehamaCALIFORNIA11996
LockwoodCALIFORNIA12023
Mark WestCALIFORNIA12017
Waterman GapCALIFORNIA12025
Glen EllenCALIFORNIA11972
PescaderoCALIFORNIA12009

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