BirdAnalyst
Species · South Dakota · BBS 2025 Release · 1966–2024

Violet-green Swallow Population Trend in South Dakota

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Violet-green Swallow in South Dakota has edged up: up 19% on the route-weighted index since 1969.

+19%Since 1969TrendPercent 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 →
18Routes 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 South DakotaNotable 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 South Dakota. See the full index history below.

Violet-green Swallow Population Forecast in South Dakota

If the recent trend holds, Violet-green Swallow in South Dakota is projected to rise about 18% by 2029 — from 0.95 in 2024 to a central estimate of 1.1 (95% range 0.27–2.0). A 5-year backtest shows a typical error of ±189.5%, with 40% of held-out values landing inside the 95% band.

+18%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 →
0.27–2.095% 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 →
±189.5%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 South Dakota is projected to rise about 18% by 2029 — from 0.95 in 2024 to a central estimate of 1.1 (95% range 0.27–2.0). A 5-year backtest shows a typical error of ±189.5%, with 40% of held-out values landing inside the 95% band.19672029
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 →
20251.10.241.9
20261.10.252.0
20271.10.262.0
20281.10.262.0
20291.10.272.0

Violet-green Swallow Survey Routes in South Dakota

Routes recording Violet-green Swallow in South Dakota.
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 →
Roubaix Lk2519911967
Pleasant Val1420181994
Reva1020241987
Long Draw1020241993
Lightning Cr620221992
Black Fox520171994
Norbeck520011992
Hazelrodt420221992
Rochford320141992
Owanka319991999
Englewood220181992
Elk Mountain220001992
Silver City220121992
Ardmore120132013
S. Pioneer120232023
Hill City120131994
Wind Cave Np120232003
Custer120241967

Violet-green Swallow Population Trend in Other States

alaskaarizonacaliforniacoloradoidahomontananebraskanevadanew-mexiconorth-dakotaoregontexasutahwashingtonwyoming

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