Anas fulvigula
mottled duck

Mottled ducks are found only in North America and are year-round residents. They are found in high densities in the intermediate marshlands of Louisiana and Southern Texas. Their population is very dense in the state of Florida from Alachua County to Cape Sable. However, they are found in the highest numbers in the wetlands around Lake Okeechobee and the areas around the Upper St. Johns River. They are also found in small numbers around the Gulf of Mexico, Alabama and the Mississippi coastal borders (approximately one-eighth of the population). A very small population was found as far south as Vera Cruz, Mexico. (Moorman and Gray, 1994)

In Florida, mottled ducks are found in freshwater wetlands, ditches, wet prairies and flooded marshes. In some seasons, mottled ducks are also found in rice and flooded fallow fields. In some cases, they have been found in small numbers in mosquito control areas. They stay in the same area year-round.

In Texas and Louisiana, mottled ducks are found fresh and saltwater marshes and brackish ponds. These areas are full of vegetation such as bulrush, long grasses, rice, cutgrass and bultongue. (Florida Fish and Wildlife, 2004; Moorman and Gray, 1994)

Mottled ducks are brown and are not easily distinguished from American black ducks (Anas rubripes). They have an iridescent blue speculum and buffy plumage, which makes them appear lighter than other species. They lack a few features that other ducks have such as white anterior edges on the speculum. These ducks appear to be uniformly dark from a distance. Mottled ducks are sexually dimorphic. The bills of males are bright yellow, but are drab colored in females. The females are grayer whereas the males are very brown in color. The tails of the males have a faint pattern but the tails of the females are patternless. Both sexes have blackish-brown upper sides and undersides. Both also have a smoke-gray U-shaped stripe on their undersides. They weigh from 810 to 1330 g and are 50 to 61 cm long with wingspans from 243 to 270 cm. Males tend to be larger than females. (Moorman and Gray, 1994; The American Ornithologists Union, 1992)

Mottled ducks have relatively short lifespans, on average they live for only 2 years. They have an annual mortality rate of about 50%. The longest known lifespan in the wild is thirteen years. The expected lifespan in the wild is five years. The expected lifespan in captivity is twenty years. (Florida Fish and Wildlife, 2004; Moorman and Gray, 1994; The American Ornithologists Union, 1992)

Mottled ducks have the ability to walk well on land (waddling) and are strong swimmers. They have strong, deep wing beats which result in direct and slow flight. In general, males are more aggressive than females, except when females have young. Their territories are usually 10 to 130 m^2, but are generally 40 m^2.

Mottled ducks have many behaviors to show aggression or fear, including: bill threats (the bird raises its beak to ward off predators and intruders), chasing, biting, inciting (when an unpaired female turns her head toward males to gain their attention), gesture-of-repulsion (a female holds her head close to her body and remains in a crouched position to ward off potential and unwanted mates), extra-pair copulation flights (a male tries to overtake/overpower a female that is not his usual mate) and pursuit flights (two males try to overtake one female in order to mate). (Moorman and Gray, 1994; Pranty, 2002; The American Ornithologists Union, 1992)

Home Range

We do not have information on home range for this species at this time.

Mottled ducks communicate with each other by making noise and displaying (see Mating Systems and Behavior).

Their sounds resemble those of mallards. The males have a low raspy "“raeb"” call. A single call note is an alarm signal and two notes together signify either courtship or conversational calls. The females also have a low, raspy call. It starts out high pitched and lowers in pitch throughout the call. Female calls consist of six notes, the second one is the highest pitched. When the female is alerted, she lets out three or four quick quacks. The female uses a "gagg" note when she is inciting (attracting) her mate. (Moorman and Gray, 1994)

Mottled ducks are carnivors and herbivores. They eat aquatic invertebrates and small fish. They often eat snails, crayfish, beetles, dragonfly nymphs, fish and midge larvae. Invertebrates make up from 1 to 40 percent of their diet. They also eat seeds, grasses, aquatic vegetation and rice.

Mottled ducks usually feed in pairs in the fall and winter. During the summer, they may feed in small groups of about twenty. From August through October (especially in the rice fields) they often feed in flocks of around three thousand. When the ducks feed alone, they search the marshlands for seeds and invertebrates by sitting on the water and tipping their heads under water (a behavior called dabbling). They rarely dive for food, but when they do, it is for minnows. (Moorman and Gray, 1994)

To escape from predators, most adults fly away. If they are ducklings and molting adults and are unable to fly, they dive underwater or hide in brush. The adult females are very protective of their broods and quack loudly at any approaching intruders.

Mammalian predators feed on eggs, nesting females, ducklings and adults during molting season. Some of these predators include gray fox (Urocyon cinereoargenteus), red fox (Vulpes vulpes), American mink (Neovison vison), river otters (Lontra canadensis), striped skunks (Mephitis mephitis), ground squirrels (genus Spermophilus) and raccoons (Procyon lotor). Northern harriers (Circus cyaneus) and peregrine falcons (Falco peregrinus) also prey on mottled ducks. In Florida, alligators (Alligator mississippiensis) eat the ducklings and some flightless adults. Snapping turtles (Chelydra serpentina), bullfrogs (Rana catesbeiana) and bass (Micropterus salmoides) also prey on ducklings. (Moorman and Gray, 1994; Pranty, 2002; The American Ornithologists Union, 1992)

Mottled ducks eat aquatic invertebrates and small fish, and help to regulate their populations. Mammals, birds of prey and other animals eat mottled ducks and help regulate their population. Their consumption of vegetation around their habitats prevents over-growth of these plants. (Florida Fish and Wildlife, 2004; Moorman and Gray, 1994; Pranty, 2002; The American Ornithologists Union, 1992)

There are no known adverse affects of mottled ducks on humans.

Mottled ducks often help control mosquito populations and are hunted by humans for food. In addition, their feathers are used to make a good quality down. (Pranty, 2002)

In Florida, mottled ducks have lost 3.7 million acres of wetland habitat due to drainage for citrus orchards and improved pastures for cattle. In Texas and Louisiana, many of the wetlands have been depleted as a result of industrialization, urbanization, coastal erosion and drainage (approximately 102 to 150 sqaure kilometers are destroyed per year). Feral mallard ducks (which are kept as pets) mate with mottled ducks, which decreases the number of pure mottled ducks in the population. Mottled ducks also tend to breed with other species of ducks, which also decreases their genetic representation in the population. The effects of hunting are undetermined for this species.

Mottled ducks are protected under the US Migratory Bird Treaty Act. (CITES, 2004; NatureServe, 2003; USGS, 2002)