BirdAnalyst
Species · Utah · BBS 2026 Release · 1966–2025

Violet-green Swallow Population Trend in Utah

All statesAerial insectivores

Violet-green Swallow in Utah has surged: up 106% on the route-weighted index since 1970.

+106%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 →
96Routes 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 →
57YearsYears 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 UtahNotable 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 →

Violet-green Swallow has surged in Utah: up 106% on the route-weighted index since 1970.

Violet-green Swallow Population Forecast in Utah

If the recent trend holds, Violet-green Swallow in Utah is projected to stay roughly flat through 2030, near 3.3 (95% range 0.00–7.1). A 5-year backtest shows a typical error of ±30.5%, with 100% of held-out values landing inside the 95% band.

+0%Change by 2030TrendPercent 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 →
3.3Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–7.195% 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 →
±30.5%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 Utah is projected to stay roughly flat through 2030, near 3.3 (95% range 0.00–7.1). A 5-year backtest shows a typical error of ±30.5%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20263.40.007.2
20273.40.007.2
20283.40.007.1
20293.40.007.1
20303.30.007.1

Violet-green Swallow Survey Routes in Utah

Routes recording Violet-green Swallow in Utah.
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 →
Hyrum3319791975
Moab3220251986
La Sal2920001994
Hardware Ranch2820181994
Canyonlands2620061991
Main Canyon2520251987
Pine Creek2520131998
La Sal 22020062003
E. Bear Lake1920251997
Bryce Canyon1820251990
Woodruff1720252002
Randolph1620241992
Navajo Lake1520251968
Boulder1520251971
Hill Creek1519951993
Alton1420191998
Kamas1320251997
Arches Np1320101989
Monticello1220251998
Logan Canyon1120191997
Newcastle1020221997
Hanna920241997
Lake Powell820091993
Ant Flat-Ogden Can620251997
Wasatch Nf620212002

Violet-green Swallow Population Trend in Other States

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Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.