BirdAnalyst
Species · BCR 34 · BBS 2025 Release · 1966–2024

Black-bellied Whistling-Duck In Sierra Madre Occidental

All regionsSierra Madre OccidentalWaterfowl

Black-bellied Whistling-Duck in Sierra Madre Occidental has fallen sharply: down 50% on the route-weighted index since 1989.

-50%Since 1989TrendPercent 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 →
16YearsYears 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-bellied Whistling-Duck has fallen sharply in Sierra Madre Occidental: down 50% on the route-weighted index since 1989.

Routes In Sierra Madre Occidental

Routes recording Black-bellied Whistling-Duck in Sierra Madre Occidental.
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 →
Peña BlancaARIZONA21997
AmadoARIZONA22014
PatagoniaARIZONA12012

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