BirdAnalyst
Species · New Jersey · BBS 2025 Release · 1966–2024

Black-billed Cuckoo Population Trend in New Jersey

All statesGeneralists

Black-billed Cuckoo in New Jersey has fallen sharply: down 68% on the route-weighted index since 1968.

-68%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 →
30Routes 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 →
54YearsYears 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 New JerseyNotable 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 New Jersey: down 68% on the route-weighted index since 1968.

Black-billed Cuckoo Population Forecast in New Jersey

If the recent trend holds, Black-billed Cuckoo in New Jersey is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.69). A 5-year backtest shows a typical error of ±38.6%, 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 →
0.00–0.6995% 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 →
±38.6%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 New Jersey is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.69). A 5-year backtest shows a typical error of ±38.6%, 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 →
20250.020.000.71
20260.010.000.70
20270.000.000.69
20280.000.000.69
20290.000.000.69

Black-billed Cuckoo Survey Routes in New Jersey

Routes recording Black-billed Cuckoo in New Jersey.
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 →
Midvale319801970
Dover320151977
Spraguetown 2220072005
Toms River219691969
Albion219901966
Bennett Mill219711967
Woodbury Hgt120192008
Greenwich119771977
Six Points120031981
Ancora119761968
Sandbrook120171970
Holmansville119861969
Clarksville119791979
New Bedford119891969
Croton120071978
Hope119901971
Kemah Lake120181980
Bloomsbury120161969
High Point120241988
Keyport120041991
Cranbury119971988
Friendship120191977
Pomona120081978
Villas119811979
Spraguetown119911977

Black-billed Cuckoo Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanew-hampshirenew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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