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

Vaux's Swift In Coastal California

All regionsCoastal CaliforniaAerial insectivores

Vaux's Swift in Coastal California has increased: up 34% on the route-weighted index since 1977.

+34%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 →
18Routes 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 →
38YearsYears 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 stay roughly flat through 2029, near 0.11 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±179.4%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.11Projected 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 →
0.00–0.2495% 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 →
±179.4%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, Vaux's Swift in Coastal California is projected to stay roughly flat through 2029, near 0.11 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±179.4%, 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 →
20250.100.000.23
20260.100.000.23
20270.110.000.24
20280.110.000.24
20290.110.000.24

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
Waterman GapCALIFORNIA22024
Angelus OaksCALIFORNIA21989
Cal Hot SpgsCALIFORNIA22014
FairfaxCALIFORNIA11980
OnoCALIFORNIA12011
Mt BaldyCALIFORNIA12015
TehamaCALIFORNIA11996
LockwoodCALIFORNIA12023
Mark WestCALIFORNIA12017
Glen EllenCALIFORNIA11972
PescaderoCALIFORNIA12009

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