BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Vaux's Swift In Great Basin

All regionsGreat BasinAerial insectivores

Vaux's Swift in Great Basin has surged: up 223% on the route-weighted index since 1970.

+223%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 →
57Routes 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 →
55YearsYears 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 →

Vaux's Swift has surged in Great Basin: up 223% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Vaux's Swift in Great Basin is projected to fall about 22% by 2029 — from 0.44 in 2024 to a central estimate of 0.34 (95% range 0.06–0.63). A 5-year backtest shows a typical error of ±34%, with 100% of held-out values landing inside the 95% band.

-22%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 →
0.06–0.6395% 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 →
±34%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 Great Basin is projected to fall about 22% by 2029 — from 0.44 in 2024 to a central estimate of 0.34 (95% range 0.06–0.63). A 5-year backtest shows a typical error of ±34%, 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 →
20250.330.050.62
20260.340.050.62
20270.340.050.62
20280.340.060.62
20290.340.060.63

Routes In Great Basin

Routes recording Vaux's Swift in Great Basin.
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 →
Badger CreekOREGON212024
KendallWASHINGTON192024
GlacierWASHINGTON92024
Camp ShermanOREGON81994
Index 2WASHINGTON82023
Barnes ValOREGON61987
LeavenworthWASHINGTON62023
Mt HoodOREGON52023
IndexWASHINGTON51971
AsotinWASHINGTON51998
RonaldWASHINGTON52018
DorrisCALIFORNIA42015
Iron GateCALIFORNIA42019
Davis LakeOREGON42023
TwispWASHINGTON42024
NubieberCALIFORNIA31997
Modoc PointOREGON32001
SnowdenWASHINGTON32023
CarltonWASHINGTON32021
WaitsburgWASHINGTON32003
BartleCALIFORNIA21980
Fall River MillsCALIFORNIA22011
ImnahaOREGON22024
Dell SpringOREGON21990
PaisleyOREGON21985

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