BirdAnalyst
Species · BCR 37 · BBS 2025 Release · 1966–2024

Black-bellied Whistling-Duck In Gulf Coastal Prairie

All regionsGulf Coastal PrairieWaterfowl

Black-bellied Whistling-Duck in Gulf Coastal Prairie has surged: up 19× on the route-weighted index since 1969.

19×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 →
57YearsYears 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 19× 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 2029, near 15 (95% range 7.9–22). A 5-year backtest shows a typical error of ±36.6%, with 80% of held-out values landing inside the 95% band.

-9%Change 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 →
15Projected 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 →
7.9–2295% 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 →
±36.6%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 2029, near 15 (95% range 7.9–22). A 5-year backtest shows a typical error of ±36.6%, with 80% of held-out values landing inside the 95% band.19672029
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 →
2025147.021
2026147.321
2027147.521
2028157.722
2029157.922

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
WinnieTEXAS542024
Loyola BeachTEXAS402009
Forked Island 2LOUISIANA392011
Lag AtascosaTEXAS352024
Bayside 2TEXAS352004
EstherLOUISIANA282024
Port AcresTEXAS282024
Bayside 3TEXAS272024
Ltl ChenierLOUISIANA232024
Sabine NwrLOUISIANA192008
KatyTEXAS172024
Loyola Beach 2TEXAS172024
KaplanLOUISIANA162023
Oyster LakeTEXAS162024
Hackberry 2LOUISIANA122024
StowellTEXAS122023
RichardLOUISIANA92023
PetronilaTEXAS82023
WoodlawnLOUISIANA72021
Forked IslandLOUISIANA62024
DanburyTEXAS62024
Rock IslandTEXAS62023
BaysideTEXAS62003
Moon Lake 2TEXAS62024

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