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

Yellow-billed Cuckoo Population Trend in South Carolina

All statesGeneralists

Yellow-billed Cuckoo in South Carolina has edged down: down 23% on the route-weighted index since 1968.

-23%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 →
51Routes 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 →
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 Yellow-billed Cuckoo Trends in South CarolinaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Yellow-billed Cuckoo in South Carolina. See the full index history below.

Yellow-billed Cuckoo Population Forecast in South Carolina

If the recent trend holds, Yellow-billed Cuckoo in South Carolina is projected to rise about 59% by 2029 — from 3.0 in 2024 to a central estimate of 4.7 (95% range 1.5–7.9). A 5-year backtest shows a typical error of ±92.6%, with 80% of held-out values landing inside the 95% band.

+59%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 →
4.7Projected 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 →
1.5–7.995% 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 →
±92.6%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, Yellow-billed Cuckoo in South Carolina is projected to rise about 59% by 2029 — from 3.0 in 2024 to a central estimate of 4.7 (95% range 1.5–7.9). A 5-year backtest shows a typical error of ±92.6%, with 80% 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 →
20254.81.68.0
20264.81.67.9
20274.71.67.9
20284.71.57.9
20294.71.57.9

Yellow-billed Cuckoo Survey Routes in South Carolina

Routes recording Yellow-billed Cuckoo in South Carolina.
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 →
Salem Xrd1020191982
Kingstree1020102010
Ridgeway1020212010
Dillon920211970
Sandhills920241994
Plum Branch820241977
Lowrys820212017
Bennettsville820171998
New Holland720241968
Pendleton719761966
Olar720191998
Pinewood720191998
Prosperity720241992
Mount Pisgah620211998
Holly Hill520231972
Coward520221966
Green Sea520242010
Carvers Bay520111998
Cauthens Xrd520211982
Johns Isle419791966
Hardeeville420231969
Rome420241968
Wagener420241966
Little Mtn419881966
Owings420041992

Yellow-billed Cuckoo Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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