BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Mottled Duck

AnatidaeWaterfowlAnas fulvigula

Mottled Duck has collapsed: down 78% on the route-weighted index since 1968.

-78%Since 1968TrendPercent 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 →
150RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Mottled Duck

The Mottled Duck (Anas fulvigula) is a North American member of the Ducks, Geese & Waterfowl (Anatidae). In this analysis it is grouped with the waterfowl.

Size
12–43.5 in long (30–110 cm) — a medium to large waterfowl (typical for the family)
Habitat
Lakes, ponds, rivers, marshes and sheltered coastal waters.
Diet
Aquatic plants, seeds and invertebrates, dabbled at the surface or dived for.
Range
Recorded on 150 Breeding Bird Survey routes across 8 states, most concentrated in the Peninsular Florida.
Family
Anatidae · Waterfowl

Notable Mottled Duck TrendsNotable 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 →

Mottled Duck has collapsed in surveyed states: down 78% on the route-weighted index since 1968.

Mottled Duck Population Forecast

If the recent trend holds, Mottled Duck is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±110.7%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.04Projected 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 →
0.00–0.1295% 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 →
±110.7%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, Mottled Duck is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±110.7%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.050.000.13
20260.050.000.13
20270.050.000.13
20280.040.000.12
20290.040.000.12

Where the Mottled Duck Is Detected

BBS routes recording Mottled Duck, sized by most recent count.

Mottled Duck Population Trend by State

Mottled Duck population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alabama-33%19923
Arkansasinsufficient datan/a2
Florida-77%196860
Kansasinsufficient datan/a1
Louisiana-37%196934
Mississippi-83%20014
South Carolinainsufficient datan/a2
Texas-88%196944

Mottled Duck Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Mottled Duck population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Oaks and Prairies-7%19717
Mississippi Alluvial Valley-36%199114
Southeastern Coastal Plain-48%19929
Peninsular Florida-79%196859
Tamaulipan Brushlands-41%197314
Gulf Coastal Prairie-81%196943

Mottled Duck Conservation Status

Our route-weighted index shows it down about 78% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.