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

Bank Swallow Population Trend in South Dakota

All statesAerial insectivores

Bank Swallow in South Dakota has collapsed: down 81% on the route-weighted index since 1969.

-81%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 →
41Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bank 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 →

long arc declinecomputed 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 →

Bank Swallow has collapsed in South Dakota: down 81% on the route-weighted index since 1969.

Bank Swallow Population Forecast in South Dakota

If the recent trend holds, Bank Swallow in South Dakota is projected to rise about 128% by 2029 — from 0.32 in 2024 to a central estimate of 0.72 (95% range 0.00–2.8). A 5-year backtest shows a typical error of ±299.6%, with 100% of held-out values landing inside the 95% band.

+128%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 →
0.72Projected 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 →
0.00–2.895% 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 →
±299.6%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, Bank Swallow in South Dakota is projected to rise about 128% by 2029 — from 0.32 in 2024 to a central estimate of 0.72 (95% range 0.00–2.8). A 5-year backtest shows a typical error of ±299.6%, 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 →
20250.760.002.9
20260.750.002.9
20270.740.002.9
20280.730.002.9
20290.720.002.8

Bank Swallow Survey Routes in South Dakota

Routes recording Bank 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 →
Marcus1620122002
Eagle Butte1520062006
Geddes1219741974
Promise1120151971
Wilmot1020161967
Roswell920141968
Raymond720211967
Hayes620222018
Badlands520121985
Broadland419891989
Veblen420191967
Britton420211967
Conde419691969
Harding420122001
Reva420001988
Lightning Cr419931993
Howard320211972
Crow Creek320212011
Fort Pierre320242013
Maurine320242011
Tripp220141971
Rosebud220111972
Rockyford219711968
Lacreek219971991
White River220122009

Bank Swallow Population Trend in Other States

alabamaalaskaarkansascaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandtennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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