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Species · BCR 12 · BBS 2026 Release · 1966–2025

Black-billed Cuckoo In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionForest birds

Black-billed Cuckoo in Boreal Hardwood Transition has declined: down 33% on the route-weighted index since 1968.

-33%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 →
125Routes 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 →
59YearsYears 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 →

No notable trend signals for Black-billed Cuckoo in Boreal Hardwood Transition. See the full index history below.

Black-billed Cuckoo In Boreal Hardwood Transition Population Forecast

If the recent trend holds, Black-billed Cuckoo in Boreal Hardwood Transition is projected to fall about 18% by 2030 — from 1.0 in 2025 to a central estimate of 0.82 (95% range 0.00–2.5). A 5-year backtest shows a typical error of ±48.5%, with 100% of held-out values landing inside the 95% band.

-18%Change by 2030TrendPercent 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 →
0.82Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–2.595% 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 →
±48.5%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 Boreal Hardwood Transition is projected to fall about 18% by 2030 — from 1.0 in 2025 to a central estimate of 0.82 (95% range 0.00–2.5). A 5-year backtest shows a typical error of ±48.5%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20260.910.002.6
20270.880.002.5
20280.860.002.5
20290.840.002.5
20300.820.002.5

Routes In Boreal Hardwood Transition

Routes recording Black-billed Cuckoo in Boreal Hardwood Transition.
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 →
ChaffeyWISCONSIN112022
MuskallongeMICHIGAN82019
CromwellMINNESOTA82025
Ned LakeMICHIGAN72025
CunardMICHIGAN72021
Hubbard LakeMICHIGAN71994
Beaver LakeMICHIGAN51994
Frederic 2MICHIGAN52015
GilmanWISCONSIN52025
Rib LakeWISCONSIN52025
BootjackMICHIGAN42023
FredericMICHIGAN42003
WaskishMINNESOTA42025
ChisholmMINNESOTA42023
Brocky LakeMICHIGAN32025
Lake CityMICHIGAN32009
CathroMICHIGAN32011
Sand LakeMICHIGAN32022
BackusMINNESOTA32022
Pine RiverMINNESOTA32022
HovlandMINNESOTA32021
LudeMINNESOTA32025
Sawbill CampMINNESOTA32023
Red LakeMINNESOTA32025
NebishMINNESOTA32019

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.