BirdAnalyst
Species · BCR 30 · BBS 2025 Release · 1966–2024

Black-billed Cuckoo In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastGeneralists

Black-billed Cuckoo in New England / Mid-Atlantic Coast has collapsed: down 88% on the route-weighted index since 1968.

-88%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 →
122Routes 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 →
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 SignalsNotable 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 collapsed in New England / Mid-Atlantic Coast: down 88% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Black-billed Cuckoo in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.50). A 5-year backtest shows a typical error of ±61.8%, 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 →
0.00–0.5095% 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 →
±61.8%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 England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.50). A 5-year backtest shows a typical error of ±61.8%, 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 →
20250.020.000.52
20260.010.000.51
20270.000.000.50
20280.000.000.50
20290.000.000.50

Routes In New England / Mid-Atlantic Coast

Routes recording Black-billed Cuckoo in New England / Mid-Atlantic Coast.
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 →
Lowes XrdsDELAWARE51973
E DennisMASSACHUSETTS52006
Warren 2MASSACHUSETTS52019
WarrenCONNECTICUT32005
GeorgetownDELAWARE31993
NewarkMARYLAND31981
BerlinMARYLAND31990
PrattvilleMASSACHUSETTS32018
E PepperellMASSACHUSETTS31994
Wellfleet 2MASSACHUSETTS32017
HauppaugeNEW-YORK32003
MysticCONNECTICUT22019
BuckinghamCONNECTICUT22016
No WoodburyCONNECTICUT22005
DoverDELAWARE21979
FrankfordDELAWARE22008
ElktonMARYLAND21983
Snow HillMARYLAND21968
NewburyportMASSACHUSETTS22015
HoldenMASSACHUSETTS22019
N. AndoverMASSACHUSETTS22018
Ware RiverMASSACHUSETTS22019
BrentwoodNEW-HAMPSHIRE21997
DoverNEW-HAMPSHIRE22015
East KingstonNEW-HAMPSHIRE22018

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