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

Vesper Sparrow Population Trend in South Dakota

All statesGrassland birds

Vesper Sparrow in South Dakota has declined: down 25% on the route-weighted index since 1969.

-25%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 →
62Routes 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 Vesper Sparrow 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 Vesper Sparrow in South Dakota. See the full index history below.

Vesper Sparrow Population Forecast in South Dakota

If the recent trend holds, Vesper Sparrow in South Dakota is projected to rise about 65% by 2029 — from 3.3 in 2024 to a central estimate of 5.4 (95% range 2.1–8.7). A 5-year backtest shows a typical error of ±59.3%, with 100% of held-out values landing inside the 95% band.

+65%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 →
5.4Projected 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 →
2.1–8.795% 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 →
±59.3%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, Vesper Sparrow in South Dakota is projected to rise about 65% by 2029 — from 3.3 in 2024 to a central estimate of 5.4 (95% range 2.1–8.7). A 5-year backtest shows a typical error of ±59.3%, with 100% 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 →
20255.42.28.7
20265.42.18.7
20275.42.18.7
20285.42.18.7
20295.42.18.7

Vesper Sparrow Survey Routes in South Dakota

Routes recording Vesper Sparrow 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 →
Eagle Butte6220152010
Isabel4120152009
Promise3620151972
Harding1820191967
Wilmot1720241967
Pleasant Val1520241992
Raymond1320211967
Gettysburg1320231969
Veblen1020231967
Roswell920101968
Britton920231970
Lane819991985
Hill City720131992
Elk Mountain720041992
Wind Cave Np720241999
Lennox620241968
Tripp620241967
Howard620241970
Rosebud520071967
Forbes520241977
Volga420241967
Silver City420021992
Ardmore320152013
White Lake220111973
Laplant220151971

Vesper Sparrow Population Trend in Other States

arizonacaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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