BirdAnalyst
Species · Maine · BBS 2025 Release · 1966–2024

Black-billed Cuckoo Population Trend in Maine

All statesGeneralists

Black-billed Cuckoo in Maine has fallen sharply: down 71% on the route-weighted index since 1971.

-71%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 →
58Routes 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 →
50YearsYears 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 MaineNotable 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 fallen sharply in Maine: down 71% on the route-weighted index since 1971.

Black-billed Cuckoo Population Forecast in Maine

If the recent trend holds, Black-billed Cuckoo in Maine is projected to fall about 100% by 2029 — from 0.21 in 2024 to a central estimate of 0.00 (95% range 0.00–1.00). A 5-year backtest shows a typical error of ±351.6%, with 100% of held-out values landing inside the 95% band.

-100%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 →
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 →
0.00–1.0095% 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 →
±351.6%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 Maine is projected to fall about 100% by 2029 — from 0.21 in 2024 to a central estimate of 0.00 (95% range 0.00–1.00). A 5-year backtest shows a typical error of ±351.6%, 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 →
20250.000.001.00
20260.000.001.00
20270.000.001.00
20280.000.001.00
20290.000.001.00

Black-billed Cuckoo Survey Routes in Maine

Routes recording Black-billed Cuckoo in Maine.
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 →
Eastbrook419871977
Waite419771977
Benton319801978
Deblois320071973
Wytopitlock319791978
Biddeford220041974
Turner220021973
Warren219881973
Cooper220041975
Charleston219951977
Medway219791976
Ludlow219951972
Washburn219961995
Heron Lake219941984
Cape Neddick119941973
Westbrook120241978
Kittery Pt119941974
Newcastle120101972
Wilson Mills119931993
Bethel120162016
Greenwood120242006
Reeds120011998
South Arm120142010
Otisfield Gr120101980
Hartford120191979

Black-billed Cuckoo Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymarylandmassachusettsmichiganminnesotamissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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