BirdAnalyst
Species · BCR 22 · BBS 2025 Release · 1966–2024

Black-billed Cuckoo In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieGeneralists

Black-billed Cuckoo in Eastern Tallgrass Prairie has collapsed: down 89% on the route-weighted index since 1968.

-89%Since 1968TrendPercent 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 →
188Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Eastern Tallgrass Prairie: down 89% on the route-weighted index since 1968.

Black-billed Cuckoo In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Black-billed Cuckoo in Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.20). A 5-year backtest shows a typical error of ±142.6%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–0.2095% 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 →
±142.6%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, Black-billed Cuckoo in Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.20). A 5-year backtest shows a typical error of ±142.6%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.000.000.20
20260.000.000.20
20270.000.000.20
20280.000.000.20
20290.000.000.20

Routes In Eastern Tallgrass Prairie

Routes recording Black-billed Cuckoo in Eastern Tallgrass Prairie.
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 →
McfallMISSOURI42024
HolcombILLINOIS32008
GeneseoILLINOIS32013
ComptonILLINOIS31973
WalesIOWA32018
WashtaIOWA32003
AustinMINNESOTA32018
HuntsvilleMISSOURI32011
ElmoMISSOURI32023
Mill CreekILLINOIS22007
PutnamILLINOIS21990
ChandlervillILLINOIS21973
Deer CreekILLINOIS21997
MilfordILLINOIS22007
ConcordILLINOIS22011
RosamondILLINOIS21978
CaledoniaILLINOIS22016
SenecaILLINOIS22021
Grape CreekILLINOIS22019
GalvestonINDIANA22007
SwayzeeINDIANA21981
MilroyINDIANA21980
BrookvilleINDIANA21995
WallaceINDIANA22002
MelroseIOWA22010

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