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

White-throated Swift Population Trend in Colorado

All statesAerial insectivores

White-throated Swift in Colorado has surged: up 244% on the route-weighted index since 1973.

+244%Since 1973TrendPercent 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 →
59Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable White-throated Swift Trends in ColoradoNotable 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 →

White-throated Swift has surged in Colorado: up 244% on the route-weighted index since 1973.

White-throated Swift Population Forecast in Colorado

If the recent trend holds, White-throated Swift in Colorado is projected to rise about 152% by 2029 — from 0.44 in 2024 to a central estimate of 1.1 (95% range 0.35–1.9). A 5-year backtest shows a typical error of ±114.9%, with 80% of held-out values landing inside the 95% band.

+152%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 →
1.1Projected 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 →
0.35–1.995% 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 →
±114.9%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, White-throated Swift in Colorado is projected to rise about 152% by 2029 — from 0.44 in 2024 to a central estimate of 1.1 (95% range 0.35–1.9). A 5-year backtest shows a typical error of ±114.9%, with 80% of held-out values landing inside the 95% band.19702029
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 →
20251.10.311.8
20261.10.321.9
20271.10.331.9
20281.10.341.9
20291.10.351.9

White-throated Swift Survey Routes in Colorado

Routes recording White-throated Swift in Colorado.
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 →
Rosevale1820242009
Castleton1019911991
Rifle Falls1020211998
Douglas Pass620241982
Uncompahgre620191990
Piceance Basin620031998
Cortez620061988
Dolores Riv519951995
Thomasville520061993
Paonia520241992
Lizard Head Pass520152001
Aspen419901979
Wray Gulch420231988
Tarryall420142014
Yellowjacket Pass420241998
Harmony320231973
Mesaverde Np320241996
Lake City320032003
Baxter Pass320241996
Guanella Pas320091997
Westcliffe319991999
Yampa220221970
Dolores219841972
Cortez 2220152010
Red Cliff220241994

White-throated Swift Population Trend in Other States

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