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

Black-billed Cuckoo Population Trend in South Dakota

All statesGeneralists

Black-billed Cuckoo in South Dakota has collapsed: down 94% on the route-weighted index since 1969.

-94%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 →
46Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-billed Cuckoo 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 →

Black-billed Cuckoo has collapsed in South Dakota: down 94% on the route-weighted index since 1969.

Black-billed Cuckoo Population Forecast in South Dakota

If the recent trend holds, Black-billed Cuckoo in South Dakota is projected to stay roughly flat through 2028, near 0.00 (95% range 0.00–0.77). A 5-year backtest shows a typical error of ±656.5%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.00Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.7795% 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 →
±656.5%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, Black-billed Cuckoo in South Dakota is projected to stay roughly flat through 2028, near 0.00 (95% range 0.00–0.77). A 5-year backtest shows a typical error of ±656.5%, with 100% of held-out values landing inside the 95% band.19672028
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 →
20240.000.000.77
20250.000.000.77
20260.000.000.77
20270.000.000.77
20280.000.000.77

Black-billed Cuckoo Survey Routes in South Dakota

Routes recording Black-billed Cuckoo 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 →
Conde519841983
Forbes319871977
Isabel320132013
Howard220131970
White Lake219791976
Crow Creek220081972
Gettysburg219711969
Promise220111971
Custer219821982
Harding219991978
Badlands219971982
French Creek220001997
Lennox120071967
Tripp119981967
Geddes119971968
Chamberlain120111968
Winner120121988
Rosebud119681968
Rockyford119871987
Volga120061973
Raymond120151967
Roswell119971969
Broadland119991978
Lane119861967
Ft Thompson120061969

Black-billed Cuckoo Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandtennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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