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Species · Arizona · BBS 2026 Release · 1966–2025

Violet-green Swallow Population Trend in Arizona

All statesAerial insectivores

Violet-green Swallow in Arizona has surged: up 109% on the route-weighted index since 1970.

+109%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 →
52Routes 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 ArizonaNotable 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 Arizona: up 109% on the route-weighted index since 1970.

Violet-green Swallow Population Forecast in Arizona

If the recent trend holds, Violet-green Swallow in Arizona is projected to fall about 44% by 2030 — from 10 in 2025 to a central estimate of 5.7 (95% range 2.6–8.8). A 5-year backtest shows a typical error of ±17.5%, with 80% of held-out values landing inside the 95% band.

-44%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 →
5.7Projected 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 →
2.6–8.895% 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 →
±17.5%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 Arizona is projected to fall about 44% by 2030 — from 10 in 2025 to a central estimate of 5.7 (95% range 2.6–8.8). A 5-year backtest shows a typical error of ±17.5%, with 80% 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 →
20265.62.58.7
20275.62.58.7
20285.62.58.7
20295.62.58.7
20305.72.68.8

Violet-green Swallow Survey Routes in Arizona

Routes recording Violet-green Swallow in Arizona.
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 →
Happy Jack9720251977
Dry Park8220251992
Alpine7620251992
Sprucedale3720251992
Williams3620251993
Rucker2720011995
Blue2519911974
Pinetop2520221993
Tsaile2420231993
Aztec Peak2319781974
Laguna1719861986
Tonto Vill.1720251992
Sawmill1520141988
Forest Lakes1420251992
Mormon Lake1319751968
Prescott1220251975
Flagstaff1120251988
Maine1020251992
Mt. Graham1020251995
Cow Springs920211993
San Simon619821974
Sunizona619961970
Clay Spring520091988
Round Rock419761968
Bartlett Res420252009

Violet-green Swallow Population Trend in Other States

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