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Species · Tennessee · BBS 2025 Release · 1966–2024

Black-billed Cuckoo Population Trend in Tennessee

All statesGeneralists

Black-billed Cuckoo in Tennessee has edged down: down 16% on the route-weighted index since 1971.

-16%Since 1971TrendPercent 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 →
15Routes 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 →
20YearsYears 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 TennesseeNotable 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 Black-billed Cuckoo in Tennessee. See the full index history below.

Black-billed Cuckoo Population Forecast in Tennessee

If the recent trend holds, Black-billed Cuckoo in Tennessee is projected to fall about 65% by 2026 — from 0.15 in 2021 to a central estimate of 0.05 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±70.4%, with 80% of held-out values landing inside the 95% band.

-65%Change by 2026TrendPercent 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 →
0.05Projected 2026 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1395% 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 →
±70.4%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 Tennessee is projected to fall about 65% by 2026 — from 0.15 in 2021 to a central estimate of 0.05 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±70.4%, with 80% of held-out values landing inside the 95% band.19682026
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 →
20220.050.000.13
20230.050.000.13
20240.050.000.13
20250.050.000.13
20260.050.000.13

Black-billed Cuckoo Survey Routes in Tennessee

Routes recording Black-billed Cuckoo in Tennessee.
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 →
Tiptonville420212021
Glen219721972
Smokey Jct120181968
Oliver Spgs119831983
Mcfarland119841971
Climer119731971
Jones Gap119831983
Sweetlips119971997
Fish Springs120101968
Pawpaw 2120212013
Petersburg119831983
Silver Pt119941985
Union Hill119711968
Jasper119851971
Soddy119781978

Black-billed Cuckoo Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-dakotatexasvermontvirginiawest-virginiawisconsinwyoming

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