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

Violet-green Swallow Population Trend in Colorado

All statesAerial insectivores

Violet-green Swallow in Colorado has increased: up 46% on the route-weighted index since 1970.

+46%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 →
109Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Violet-green Swallow 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 →

No notable trend signals for Violet-green Swallow in Colorado. See the full index history below.

Violet-green Swallow Population Forecast in Colorado

If the recent trend holds, Violet-green Swallow in Colorado is projected to stay roughly flat through 2029, near 9.1 (95% range 2.5–16). A 5-year backtest shows a typical error of ±44.1%, with 100% of held-out values landing inside the 95% band.

+6%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 →
9.1Projected 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 →
2.5–1695% 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 →
±44.1%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, Violet-green Swallow in Colorado is projected to stay roughly flat through 2029, near 9.1 (95% range 2.5–16). A 5-year backtest shows a typical error of ±44.1%, 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 →
20258.92.416
20269.02.416
20279.02.516
20289.12.516
20299.12.516

Violet-green Swallow Survey Routes in Colorado

Routes recording Violet-green Swallow 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 →
Aspen8920241979
Colona 26120212015
Buford6020241973
Dolores Riv5920241988
Cokedale5720241995
Stillwater Pass4020091998
Pagosa Spgs3519821968
Colona3320141972
Dunckley Pas3320241992
Fox Creek2920241993
Gold Hill 22820242018
Parlin2620231968
Gold Hill2620121998
Lizard Head Pass2620242001
Lake City 22320242016
Mcphee Res.2320241996
Cheesman Lk2220241969
Baxter Pass2220241994
Mesaverde Np2220241996
Douglas Pass1920241982
Owl Creek Pass1920241998
Haycamp Mesa1920241998
Westcliffe1720241998
Yampa1620231969
Wilson Creek1620241990

Violet-green Swallow Population Trend in Other States

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