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

Violet-green Swallow Population Trend in Idaho

All statesAerial insectivores

Violet-green Swallow in Idaho has declined: down 31% on the route-weighted index since 1970.

-31%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 →
56Routes 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 IdahoNotable 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 Idaho. See the full index history below.

Violet-green Swallow Population Forecast in Idaho

If the recent trend holds, Violet-green Swallow in Idaho is projected to fall about 16% by 2030 — from 5.1 in 2025 to a central estimate of 4.3 (95% range 0.00–9.0). A 5-year backtest shows a typical error of ±18.6%, with 100% of held-out values landing inside the 95% band.

-16%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 →
4.3Projected 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 →
0.00–9.095% 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 →
±18.6%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 Idaho is projected to fall about 16% by 2030 — from 5.1 in 2025 to a central estimate of 4.3 (95% range 0.00–9.0). A 5-year backtest shows a typical error of ±18.6%, 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 →
20264.20.008.9
20274.20.008.9
20284.20.008.9
20294.30.009.0
20304.30.009.0

Violet-green Swallow Survey Routes in Idaho

Routes recording Violet-green Swallow in Idaho.
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 →
Magic Mtn4220251987
Challis3120251975
Coolin3020251986
Centerville2720251985
Almo2120251988
Golden1720151987
Nezperce1420121968
Dougal Res1120251988
Nezperce Nf1119991992
Leadore920241974
Daniels Res819911989
Gifford720171989
Craters719931981
Baldy Mountain720152015
Pierce720071990
Naples620251972
Baker520241974
Cobalt520251989
Iron Springs520041989
Lolo Pass420191992
Ririe420231988
Featherville420221989
Avery320221979
Cape Horn320152006
Dubois320231973

Violet-green Swallow Population Trend in Other States

alaskaarizonacaliforniacoloradomontananebraskanevadanew-mexiconorth-dakotaoregonsouth-dakotatexasutahwashingtonwyoming

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