BirdAnalyst
Species · BCR 16 · BBS 2025 Release · 1966–2024

Black-billed Cuckoo In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGeneralists

Black-billed Cuckoo in Southern Rockies / Colorado Plateau has collapsed: down 84% on the route-weighted index since 1970.

-84%Since 1970TrendPercent 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 →
3Routes 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 →
15YearsYears 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 Southern Rockies / Colorado Plateau: down 84% on the route-weighted index since 1970.

Routes In Southern Rockies / Colorado Plateau

Routes recording Black-billed Cuckoo in Southern Rockies / Colorado Plateau.
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 →
Fox ParkWYOMING22000
BrookhurstWYOMING11984
Sybille CynWYOMING11998

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