SCIENTIFIC NAME:
Oxyura jamaicensis
OTHER NAMES:
Butterball, bull-necked teal
STATUS:
Common in winter, fairly common to rare in fall and spring, and occasional in summer in Tennessee Valley region. In other regions, fairly common in winter, fairly common to rare in spring and fall, and occasional in summer. Low Conservation Concern.
DESCRIPTION:
Ruddy duck (Oxyura jamaicensis rubida) is a rather small duck, about 14 to 16 inches in length, with a thick neck and chunky body. A fan-shaped tail of stiff feathers is a distinguishing characteristic. The belly and breast are white with bars of gray, and the large feet are blue-gray. The rest of the plumage is gray-brown, except for the tail, which is nearly black in color. The bill of the ruddy duck is concave and changes color from gray-black to sky-blue during spring. Juvenile males develop a white cheek patch that distinguishes them from adult or immature females. Body feathers of adult males turn a rich, chestnut-orange color during the breeding season. Even though some males have chestnut-colored covert feathers, their wings alone do not reveal enough differences to separate males from females.
DISTRIBUTION:
There are six species of stifftail ducks that belong to the genus Oxyura. Three of these are races of ruddy ducks. One occurs in North America and the other two are found in the Andes of South America. The breeding range of Oxyura jamaicensis rubida encompasses the northern prairies, Ontario, Quebec, valleys and basins of the western U.S., and a few breeding colonies found in the subarctic. Primary wintering grounds for ruddies occur in Pacific and Atlantic coastal states, as well as coastal areas of Mexico, Texas, and Louisiana. Ruddy ducks use areas in Alabama as migrational rest stops on their way to coastal areas of Florida.
HABITAT:
Nesting occurs in pothole areas that are from less than an acre to four acres in size. They prefer emergent vegetation in depths of 10 to 12 inches for nest sites. Brood rearing habitat consists of both deep marshes and open water. Ruddy ducks search for coastal marshes with water ranging from two to 10 feet deep as their primary wintering areas. Freshwater areas that contain vegetation such as wigeon grass, pondweeds, and wild celery are their choice feeding areas, but brackish estuarine areas also provide favorable wintering habitat.
FEEDING HABITS:
Ruddy ducks spend an average of 20 seconds under water during each dive searching for items such as pondweed seeds and tubers, bulrush seeds, muskgrass, and wigeon grass. Adults consume some animal matter on the breeding grounds, and juveniles rely heavily on protein-rich animals like midge larvae and mollusks for proper development. On the wintering grounds, they are primarily vegetarians, but will turn to animal life when plant matter is scarce. Shrimp, bivalve clams, snails, and other invertebrates often comprise the menu for ruddies when wintering in brackish estuarine areas. Wigeon grass, coontail, pondweeds, and wild celery are their top choices in freshwater estuarine areas.
LIFE HISTORY AND ECOLOGY:
Ruddy ducks have been observed exhibiting polygamous and monogamous behavior. Some males leave their mates at the beginning of incubation, while others have been seen assisting females with broods. Nests are constructed from the marsh bottom to the surface. They average three inches in depth and seven to 12 inches in diameter. The average clutch size is eight eggs with a range from five to 15. Ruddy ducks practice nest parasitism, and as many as 60 eggs have been found in one dump nest. The eggs are considered huge in comparison to the size of ruddy ducks. Eggs are white, with a thick shell and average size of 2.5 inches by 1.8 inches. Eggs are generally laid at the rate of one egg per day, with an incubation period of 23 days from the date of last egg laid. Nest success rates are normally very high, reaching over 70 percent in some instances. Some nests fail due to predation, flooding, desertion, or drought. Renesting is uncommon.
REFERENCES:
Bellrose, F.C. 1980. Ducks, Geese, and Swans of North America. Stackpole Books, Harrisburg, PA, 540 pp.
AUTHOR:
Frank Allen, Wildlife Biologist, Division of Wildlife and Freshwater Fisheries
