BirdAnalyst
Species · South Dakota · BBS 2026 Release · 1966–2025

Willet Population Trend in South Dakota

All statesShorebirds

Willet in South Dakota has fallen sharply: down 55% on the route-weighted index since 1969.

-55%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 →
22Routes 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 Willet 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 →

Willet has fallen sharply in South Dakota: down 55% on the route-weighted index since 1969.

Willet Population Forecast in South Dakota

If the recent trend holds, Willet in South Dakota is projected to rise about 24% by 2030 — from 0.11 in 2025 to a central estimate of 0.13 (95% range 0.00–0.63). A 5-year backtest shows a typical error of ±156.9%, with 100% of held-out values landing inside the 95% band.

+24%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 →
0.13Projected 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 →
0.00–0.6395% 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 →
±156.9%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, Willet in South Dakota is projected to rise about 24% by 2030 — from 0.11 in 2025 to a central estimate of 0.13 (95% range 0.00–0.63). A 5-year backtest shows a typical error of ±156.9%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20260.150.000.64
20270.140.000.64
20280.140.000.63
20290.140.000.63
20300.130.000.63

Willet Survey Routes in South Dakota

Routes recording Willet 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 →
Forbes620091967
Ottumwa420092009
Long Lake320191967
Cottonwood220252011
Broadland220022002
Veblen219981969
Britton220131971
Ardmore219781978
White Lake120101968
Raymond120141968
Roswell119771977
Crow Creek120192005
Ft Thompson119771977
Wilmot120142014
Gettysburg120231969
Laplant119991999
Harding119881988
Cedar Pass119971997
Gorman120102010
Reva120241989
Lodgepole120241995
Lacreek120251991

Willet Population Trend in Other States

alabamacaliforniacoloradoconnecticutdelawarefloridaidaholouisianamainemarylandmassachusettsminnesotamontananebraskanevadanew-jerseynew-yorknorth-carolinanorth-dakotaoregonsouth-carolinatexasutahvirginiawyoming

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