Jason Gentry, age 12, of Butte, Mont., for his question:
HOW MANY KINDS OF DUCK ARE THERE?
Duck is the common name applied to numerous waterfowl species, mostly of a family called Anatidae. There are about 115 species that are known.
Ducks are distinguished from geese and swans by shorter necks and legs and by smaller and flatter, more streamlined, bodies. Able to migrate great distances, ducks inhabit all of the world's continents except Antarctica and all but a few of the world's islands.
The legs of ducks are placed far apart and toward the rear, making them awkward waddlers but efficient and powerful swimmers. The under plumage, or down, which is buoyant and insulating, is kept water resistant by frequent preening with oil from a gland, called the uropygial gland, at the base of the tail feathers.
Ducks have spatulate bills lined with bony notches, or lamellae, for straining plant and animal matter from water.
Male ducks, called drakes, often have iridescent wing spatula and other colorful markings that they display to the drab colored females. Pairing is seasonal and is contested for many months by other males until the bond is firmly established.
Four to 12 eggs are laid in crude, usually shoreline nests, made mostly of duck down. After 21 to 35 days the ducklings hatch. Upon drying they are called from the nest by the mother's low, piping cry.
Through parental guidance the ducklings are quickly able to swim, care for themselves and catch insects. By fall they are able to migrate.
Climatic changes and favorable tail winds set off mass migrations of ducks, which usually fly at a altitudes of 2,800 to 5,000 feet and and follow river and coastal flyways. Migrating flocks travel from 35 to 60 miles per hour and can cover 1,500 miles in a few days.
The mallard is the breed from which most domestic species of duck originate.
Most of the domestic breeds of ducks are used for meat, egg and down production. The first mallard duck was domesticated in China more than 1,000 years ago.
About 10 varieties of domestic duck exist today. White Pekins, which are raised mostly in Long Island, reach weights of about seven pounds in seven to eight weeks of age.
The Muscovy, a less common United States duck, was derived from the wild Muscovy duck of South America.
Perching ducks make up the tribe called Cairinni, or ducks that perch on tre a limbs. An example is the handsome Carolina wood duck.
Mersansers, of the tribe Mergini, are strong legged, fish eating sea ducks that dive underwater to pursue prey.
Pochards, of the tribe Aythyini, which are mostly freshwater diving ducks, include the canvasback.
Heat known for the dabbling, or surface feeding, are ducks of the tribe Anatini, which include the mallard. Dabbling ducks glean plants and small aquatic animals from the surface or from shallow bottoms and feed no deeper than they can reach in a tail up position.