BirdAnalyst
Species · BCR 37 · BBS 2026 Release · 1966–2025

Black-bellied Whistling-Duck In Gulf Coastal Prairie

All regionsGulf Coastal PrairieWaterfowl

Black-bellied Whistling-Duck in Gulf Coastal Prairie has surged: up 17× on the route-weighted index since 1969.

17×Since 1969TrendPercent 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 →
40Routes 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 increasecomputed 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 surged in Gulf Coastal Prairie: up 17× on the route-weighted index since 1969.

Black-bellied Whistling-Duck In Gulf Coastal Prairie Population Forecast

If the recent trend holds, Black-bellied Whistling-Duck in Gulf Coastal Prairie is projected to stay roughly flat through 2030, near 15 (95% range 8.3–22). A 5-year backtest shows a typical error of ±22.6%, with 80% of held-out values landing inside the 95% band.

-1%Change by 2030TrendPercent 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 →
15Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
8.3–2295% 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 →
±22.6%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-bellied Whistling-Duck in Gulf Coastal Prairie is projected to stay roughly flat through 2030, near 15 (95% range 8.3–22). A 5-year backtest shows a typical error of ±22.6%, with 80% of held-out values landing inside the 95% band.19672030
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 →
2026147.421
2027157.621
2028157.922
2029158.122
2030158.322

Routes In Gulf Coastal Prairie

Routes recording Black-bellied Whistling-Duck in Gulf Coastal Prairie.
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 →
IndianolaTEXAS622024
Hackberry 2LOUISIANA432025
Loyola BeachTEXAS402009
Forked Island 2LOUISIANA392011
Port AcresTEXAS382025
Bayside 2TEXAS352004
Lag AtascosaTEXAS342025
Moon Lake 2TEXAS312025
WinnieTEXAS282025
Bayside 3TEXAS272024
KatyTEXAS252025
Ltl ChenierLOUISIANA242025
Sabine NwrLOUISIANA192008
KaplanLOUISIANA162023
DanburyTEXAS152025
Oyster LakeTEXAS122025
Forked IslandLOUISIANA112025
PetronilaTEXAS112025
StowellTEXAS112025
Loyola Beach 2TEXAS102025
L. Atascosa NwrTEXAS102025
Vinton 2LOUISIANA92025
ChinquapinTEXAS92025
EstherLOUISIANA72025
WoodlawnLOUISIANA72021

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.