BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Vaux's Swift

ApodidaeAerial insectivoresChaetura vauxi

Vaux's Swift has surged: up 203% on the route-weighted index since 1970.

+203%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 →
253RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Vaux's Swift

The Vaux's Swift (Chaetura vauxi) is a North American member of the Swifts (Apodidae). In this analysis it is grouped with the aerial insectivores.

Size
4.5–7 in long (12–18 cm) — a small aerial bird (typical for the family)
Habitat
Open airspace over fields, water and towns; nests in cavities, earthen banks or on structures.
Diet
Flying insects caught on the wing.
Range
Recorded on 253 Breeding Bird Survey routes across 6 states, most concentrated in the Northern Pacific Rainforest.
Family
Apodidae · Aerial insectivores

Notable Vaux's Swift TrendsNotable 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. See the full index history below.

Vaux's Swift Population Forecast

If the recent trend holds, Vaux's Swift is projected to stay roughly flat through 2029, near 0.06 (95% range 0.02–0.10). A 5-year backtest shows a typical error of ±64.2%, 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 →
0.06Projected 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 →
0.02–0.1095% 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 →
±64.2%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 is projected to stay roughly flat through 2029, near 0.06 (95% range 0.02–0.10). A 5-year backtest shows a typical error of ±64.2%, 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 →
20250.060.020.10
20260.060.020.10
20270.060.020.10
20280.060.020.10
20290.060.020.10

Where the Vaux's Swift Is Detected

BBS routes recording Vaux's Swift, sized by most recent count.

Vaux's Swift Population Trend by State

Vaux's Swift population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alaskainsufficient datan/a5
California-37%197160
Idaho-76%197820
Montana-41%198214
Oregon+26%197083
Washington+53%197071

Vaux's Swift Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Vaux's Swift population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Northern Pacific Rainforest-37%197094
Great Basin+223%197057
Northern Rockies-49%197469
Sierra Nevada-65%197514
Coastal California+34%197718

Vaux's Swift Conservation Status

Our route-weighted index shows it up about 203% since 1970. Aerial insectivores have fallen sharply across the continent, a decline widely linked to dwindling insect prey.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.