BirdAnalyst
Species · BCR 36 · BBS 2025 Release · 1966–2024

Black-bellied Whistling-Duck In Tamaulipan Brushlands

All regionsTamaulipan BrushlandsWaterfowl

Black-bellied Whistling-Duck in Tamaulipan Brushlands has surged: up 217% on the route-weighted index since 1969.

+217%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 →
28Routes 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 Tamaulipan Brushlands: up 217% on the route-weighted index since 1969.

Black-bellied Whistling-Duck In Tamaulipan Brushlands Population Forecast

If the recent trend holds, Black-bellied Whistling-Duck in Tamaulipan Brushlands is projected to stay roughly flat through 2029, near 9.8 (95% range 0.00–23). A 5-year backtest shows a typical error of ±61.1%, with 100% of held-out values landing inside the 95% band.

+10%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 →
9.8Projected 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 →
0.00–2395% 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 →
±61.1%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 Tamaulipan Brushlands is projected to stay roughly flat through 2029, near 9.8 (95% range 0.00–23). A 5-year backtest shows a typical error of ±61.1%, with 100% 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 →
20259.70.0023
20269.70.0023
20279.80.0023
20289.80.0023
20299.80.0023

Routes In Tamaulipan Brushlands

Routes recording Black-bellied Whistling-Duck in Tamaulipan Brushlands.
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 →
HeidelbergTEXAS612024
Pedro CreekTEXAS542005
ProgresoTEXAS262011
KingsvilleTEXAS182024
La PryorTEXAS142017
George WestTEXAS132023
RaymondvilleTEXAS112024
HondoTEXAS92024
Agua NuevaTEXAS62014
El IndioTEXAS62001
ZapataTEXAS51987
DilleyTEXAS52023
EncinalTEXAS42010
San YgnacioTEXAS41982
SejitaTEXAS42024
MillettTEXAS42012
Millett 2TEXAS32022
RachalTEXAS22019
RandadoTEXAS22024
Mirando CityTEXAS22019
El SauzTEXAS22023
Catarina 2TEXAS22017
Encinal 2TEXAS22024
Catarina 3TEXAS22023
LaredoTEXAS22023

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