BirdAnalyst
Species · Montana · BBS 2025 Release · 1966–2024

Vaux's Swift Population Trend in Montana

All statesAerial insectivores

Vaux's Swift in Montana has declined: down 41% on the route-weighted index since 1982.

-41%Since 1982TrendPercent 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 →
14Routes In StateSurvey 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 Vaux's Swift Trends in MontanaNotable 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 Montana. See the full index history below.

Vaux's Swift Population Forecast in Montana

If the recent trend holds, Vaux's Swift in Montana is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.23). A 5-year backtest shows a typical error of ±261.2%, 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 →
0.07Projected 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 →
0.00–0.2395% 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 →
±261.2%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 in Montana is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.23). A 5-year backtest shows a typical error of ±261.2%, with 100% of held-out values landing inside the 95% band.19782029
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 →
20250.070.000.23
20260.070.000.23
20270.070.000.23
20280.070.000.23
20290.070.000.23

Vaux's Swift Survey Routes in Montana

Routes recording Vaux's Swift in Montana.
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 →
Inside Road2020122005
Pablo Res.520102010
St Regis420231985
Logan Pass320231980
Woodman319971991
Libby Dam219881984
Kalispell220241980
Fish Creek219951995
Swan Lake220242015
Ninemile120091993
Noxon120212014
Victor120072007
Arlee120221978
Thompson Riv120112007

Vaux's Swift Population Trend in Other States

alaskacaliforniaidahooregonwashington

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