The Ruddy duck is a small diving duck found in North America. These are ducks with stout, scoop-shaped bills, and long, stiff tails they often hold cocked upward. They have slightly peaked heads and fairly short, thick necks. Males have blackish caps that contrast with bright white cheeks. In summer, they have rich chestnut bodies with bright blue bills. In winter, they are dull gray-brown above and paler below with dull gray bills. Females and first-year males are brownish, somewhat like winter males but with a blurry stripe across the pale cheek patch. In flight, Ruddy ducks show solidly dark tops of the wings.
Ruddy ducks are found in southern Canada, in the United States, and Mexico. They winter in most of the United States, in Mexico and in Central America. These ducks inhabit marshy lakes, wetlands, ponds, salt bays, and estuaries.
Ruddy ducks are usually active at night and sleep during the day. They are social birds and often congregate in pairs or in small groups, however, some individuals may occur singly. Ruddy ducks spend most of their time in the water and usually come on land only during the nesting period. They are excellent swimmers and feed mainly by diving. Occasionally they forage on the surface of the water. Ruddy ducks are shy birds and if threatened, they usually dive or hide in dense aquatic vegetation. They are migratory and winter in coastal bays and unfrozen lakes and ponds. Ruddy ducks are usually silent, however, during the breeding season they become more vocal while performing courtship displays; they make some drumming and males usually produce a “chuck-chuck-chuck-chuck-churr” call.
Ruddy ducks are serially monogamous and form pairs only for one breeding season. Their breeding season occurs from May to August and during this time birds become very aggressive. They form pairs after arriving on the breeding grounds where males perform courtship displays for females. Ruddy ducks nest in dense marsh vegetation near water. The female builds the nest out of the grass, locating it in tall vegetation to hide it from predators. A typical brood contains 5 to 15 eggs which are incubated about 22 to 26 days by the female. The ducklings are quite large and fully developed (precocial) when they hatch. They leave the nest the day after hatching and are able to swim and dive well. Ducklings become independent from their mother 3 or 4 weeks after hatching, but begin to fly at around two months of age. Young Ruddy ducks become reproductively mature and are ready to breed for the first time at 1 year of age.
Ruddy ducks suffer from poor water quality, pollution, and oil spills as they are very dependent on wetlands where they spend most of their time.
The IUCN Red List and other sources don’t provide the number of the Ruddy duck total population size. According to the Ducks Unlimited resource, the population size of the North American Ruddy duck subspecies (North America, Central America, Caribbean) is 650,000 individuals; Andean ruddy duck subspecies (High Andes of Colombia): 2,500-10,000 individuals; Peruvian ruddy duck subspecies (Neotropics): 25,000-100,000 individuals. According to the Royal Society for the Protection of Birds (RSPB) resource, the total wintering population size of the Ruddy duck in the UK is 60 birds. Overall, currently, Ruddy ducks are classified as Least Concern (LC) on the IUCN Red List but their numbers today are decreasing.
Ruddy ducks play an important role in their ecosystem as predators of aquatic invertebrates and aquatic vegetation. These birds are also an important food source for many local predators including birds of prey, raccoons, mink, American crows, red foxes, herons, and gulls.