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

Willow Flycatcher Population Trend in South Dakota

All statesAerial insectivores

Willow Flycatcher in South Dakota has surged: up 179% on the route-weighted index since 1969.

+179%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 →
33Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Willow Flycatcher 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 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 →

Willow Flycatcher has surged in South Dakota: up 179% on the route-weighted index since 1969.

Willow Flycatcher Population Forecast in South Dakota

If the recent trend holds, Willow Flycatcher in South Dakota is projected to rise about 293% by 2029 — from 0.18 in 2024 to a central estimate of 0.72 (95% range 0.27–1.2). A 5-year backtest shows a typical error of ±74.7%, with 80% of held-out values landing inside the 95% band.

+293%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 →
0.27–1.295% 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 →
±74.7%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, Willow Flycatcher in South Dakota is projected to rise about 293% by 2029 — from 0.18 in 2024 to a central estimate of 0.72 (95% range 0.27–1.2). A 5-year backtest shows a typical error of ±74.7%, with 80% 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 →
20250.680.231.1
20260.690.241.1
20270.700.251.1
20280.710.261.2
20290.720.271.2

Willow Flycatcher Survey Routes in South Dakota

Routes recording Willow Flycatcher 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 →
Britton820231974
Laplant719901990
Broadland620141999
White Lake420111969
Lane419991985
Gettysburg420231976
Englewood320172017
Rochford320172017
Tripp220231967
Howard220111971
Geddes220141988
Raymond220211983
Forbes220241977
Gorman220101979
Black Fox220031998
Lane 2220142000
Lennox120181971
Chamberlain120112005
Winner120182005
Volga120231967
Roswell120101967
Crow Creek120222000
Ft Thompson119991996
Wilmot120241967
Veblen120211974

Willow Flycatcher Population Trend in Other States

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

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