Introduction

The Mottled Duck, a southern relative of the American Black Duck (Anas rubripes) and Mallard (Anas platyrhynchos), inhabits peninsular Florida and coastal marshes along the Gulf of Mexico from Alabama west and south to Tampico, Mexico. This is a dabbling species that prefers freshwater prairie ponds in Florida and brackish marsh ponds along the Gulf Coast. Although probably the least gregarious of North American Anatini, large flocks of Mottled Ducks often gather in harvested rice fields after breeding.

Mottled Ducks are seasonally monogamous. Compared to other species of ducks, pair formation occurs early, with nearly 80% of all individuals paired by November. Breeding starts in January, continuing through to July and usually peaking in March and April. Females build nests on the ground or suspended immediately above it in dense stands of grass. The pair bond usually terminates during incubation, and only females incubate eggs. Ducklings tend to hatch together over a period of about 24 hours; once hatched, the female parent leads them to nearby shallow-water wetlands that have emergent vegetation. There the ducklings find the invertebrate foods that sustain them during their period of growth. Adults eat aquatic invertebrates as well, but also seeds (especially rice in fall) and even small fish.

Wetland drainage in Florida and degradation of coastal marshes by saltwater intrusion and erosion in Louisiana and Texas pose serious conservation challenges for managers of this species. In Florida, hybridization with feral Mallards (domesticated strains released as pets) is possibly the single greatest threat to the future of the Mottled Duck as a unique species. Education of the general public about the release of domestic Mallards is an urgent conservation priority.