Oxyura jamaicensis
ruddy duck

Ruddy ducks are native to North and South America. These stiff-tailed ducks nest in western and central Canada and much of the western United States as far east as the Great Lakes region and south to central Texas, throughout Baja California, and to the transvolcanic belt in Mexico. Wintering range extends throughout most of southern North America, from California through the Great Lakes region and the Atlantic coast south of southern Maine to as far south as western Guatemala and El Salvador. Ruddy ducks were introduced to England in 1960 in Gloucestershire. From there these ducks have colonized Ireland and Belgium. Ruddy ducks introduced in Europe are migratory birds from the eastern United States and Mexico. Two subspecies including Oxyura jamaicensis ferruginea and Oxura jamaicensis andina can be found in the West Indies, Columbia, and throughout the Andes Mountains. (Gooders and Boyer, 1986; Pough, 1951)

Ruddy ducks inhabit permanent freshwater marshes, lakes, and ponds during their breeding season. These pools contain a considerable amount of vegetation in which these ducks hide their nests. During the winter ruddy ducks prefer shallow marshes and coastal bays. (Gooders and Boyer, 1986)

The morphology of ruddy ducks varies between sexes as well as seasonally. During the summer male ruddy ducks have rich chestnut necks and bodies. The crown, nape, and tail, which are held erect or horizontal to the water, are dark brown. Males have pure white faces, whereas females have a dark line across the face. Females and juveniles have barred bodies that lack any chesnut coloring. During the winter, male ruddy ducks resemble females. Their pure white face remains the primary distinguishing characteristic. Ruddy ducks have large, spatulate, pale blue bills. Males tend to be larger than females in weight and wingspan. Males are 142 to 154 mm from wing tip to wing tip and weigh from 540 to 795 g. Females are 135 to 149 mm from wing tip to wing tip and weigh 310 to 650 g. Body length is from 35 to 43 cm.

Male ruddy ducks have two molts. The prenuptial molt occurs in the summer months and reveals a plumage that is similar to that of females. The postnuptial molt occurs from August to October and reveals their winter plumage of bright chestnut. During this time the bill becomes bright blue as well. (Gooders and Boyer, 1986; Kortright, 1967)

The maximum lifespan of ruddy ducks in the wild is 13 years. However, in Great Britain, where the species is considered invasive, individuals rarely reach that age. According to the Global Invasive Species Database, those ducks banded and tracked in the wild rarely survive past 2 years. Those birds kept in captivity have an average lifespan of 2.4 years. (Hughes, 2006)

Ruddy ducks are clumsy on land because of the position of their legs on the body. Their legs are set far back on the body, making it difficult for them to walk. However, this morphology makes them exceptionally fast and agile in the water. They can dive or sink into the water with little effort. Compelled by a single power stroke of their feet these ducks dive approximately a meter below the surface until they reach the substrate, where they forage for food. While diving, the feet paddle simultaneously and wings remain closed. In order to become airborne these ducks must beat their wings rapidly and run along the surface of the water. Once in flight, ruddy ducks fly at relatively low heights above the water. This is true even during migration when they travel in medium to large sized flocks primarily at night to their summer breeding grounds.

These ducks usually occur alone, in pairs, or in small groups of eight to twelve. They rarely associate with other birds and the young tend to be aggressive toward other species. (Kortright, 1967; Pough, 1951)

Home Range

Ruddy ducks do not actively defend a territory, nor do they restrict themselves to a given home range for any part of the year.

Ruddy ducks usually don't make many calls or other sounds. During courtship, males perform an elaborate display accompanied by a call in order to attract a mate. The voice is as follows: chuck-chuck-chuck-chuck-chur-r-r; and ip-ip-ip-ip-u-cluck; and tick, tick, tick, tickety, quo-ack; as well as chica, chica, chica, chica, quak. (Kortright, 1967)

Ruddy ducks are omnivorous. Their diet consists primarily of aquatic invertebrates and vegetation. Their spatulate bill is used to sieve food material from mud taken in during diving. Primary plant material consumed includes angiosperm seeds and other green plants. Aquatic invertebrates constitute a fraction of the diet, depending on seasonal abundance, including mostly Crustacea and Chironomidae larvae and pupae. (Gooders and Boyer, 1986; Sanchez, Green, and Dolz, 2000)

Ruddy ducks have the ability to sink below the surface of the water. This adaptation allows them to elude predators. During breeding season they construct nests using surrounding vegetation. This provides shelter and camouflage to protect their eggs from known nest predators. Females may sometimes perform a display to distract predators away from nests. Females and nestlings are cryptically colored.

Eggs and nestlings are taken by predators such as racoons (Procyon lotor), mink (Neovison vison), American crows (Corvus brachyrhynchos), black-crowned night herons (Nycticorax nycticorax), ring-billed gulls (Larus delawarensis), and California gulls (Larus californicus). Adults are preyed on by red-tailed hawks (Buteo jamaicensis), great horned owls (Bubo virginianus), red foxes (Vulpes vulpes), mink (Neovison vison), and possibly Swainson's hawks (Buteo swainsoni). Ruddy ducks are also legally hunted in North America and Europe. (Brua, 1999; Gooders and Boyer, 1986; Korschgen, George, and Green, 1985; Kortright, 1967)

In the ecosystems in which they live, ruddy ducks act as predators on soft-bodied invertebrates such as chironomid midge larvae and crustaceans. They also eat aquatic vegetation. Ruddy ducks are preyed on by many organisms, including raccoons, mink, American crows, red-tailed hawks, and great horned owls. Ruddy ducks are used as a host by parasites that reside in their intestinal tracts such as Polymorphus obtusus and Corynosoma constrictum. They also act as hosts to tapeworms such as Hymenolepis cyrtoides and Diorchis excentrica.

Since their introduction to Europe in the 1960s, ruddy ducks have also impacted ecosystems by threatening native white-headed ducks (Oxyura leucocephala). Their continuing spread throughout Europe threatens white-headed ducks through hybridization and competition for nesting sites and food. For this reason ruddy ducks are considered invasive and are hunted. (Munoz-Fuentes et al., 2006; Pough, 1951; Sanchez, Green, and Dolz, 2000)

There are no adverse effects of Oxyura jamaicensis on humans.

In the past, ruddy ducks were hunted for the quality of their meat. There continues to be regulated sport hunting in the United States and Europe. (Gooders and Boyer, 1986)

Ruddy duck populations are considered stable throughout their range, and are considered a species of "Least Concern" on the IUCN list.