A duck (female) and drake (male) Mallard
Duck is the common name for any member of a variety of species of relatively short-necked, large-billed waterfowl in the Anatidae family of birds, and especially those in the subfamily Anatinae ("true ducks"). The Anatidae family also includes swans, which are larger and have a longer neck than ducks, and geese, which generally are larger and with a less pointed bill.
Ducks are mostly aquatic birds and may be found in both freshwater and marine environments. There are both wild and domestic groups.
The term "duck" sometimes is specifically for adult females and "drake" for adult males. Some use the terms "hen" and "drake," respectively.
Beyond their own individual purpose of survival, maintenance, and reproduction, ducks as a group offer numerous ecological, economic, aesthetic, and recreational benefits. They are integral to ecosystem food chains, are farmed for their feathers, eggs, and meat, are appreciated for their beauty of form, action, and color, and are a popular focus of recreational hunters.
Like other Anatidae, ducks have a broad body, partially webbed feet, a somewhat flattened bill with horny lamellae (miniature ridges, like the "teeth of a comb"), and a hard process (the "nail") at the tip of the bill, as well as a large preen gland crowned by a tuft of feathers (Grzimek et al. 2004). Anatidae are excellent at shedding water due to special oils. Ducks all have webs between their front toes.
Ducks are generally divided into three main groups. The diving ducks and sea ducks, such as the canvasback, are found on rivers and lakes and forage deep underwater. Surface feeders, or dabbling ducks, such as the mallard and wood duck, are common in ponds and marshes and feed on the surface of water or on land. The lamellae of dabbling ducks are similar to a whale's baleen, with these tiny rows of plates along the inside of the beak letting them filter water out of the side of their beaks and keep food inside (Ogden 2006). To be able to submerge more easily, the diving ducks are heavier than dabbling ducks, and therefore take a longer time in taking off to fly, whereas the dabbling ducks can take straight off. There are also fish-eating ducks, such as the mergansers, smew, and goosnader that are adapted to catch large fish and prefer open water.
Males of all Anatidae, including the ducks, have a copulatory organ that is evaginated from the cloaca for copulation (Grzimek et al. 2004). Anatidae are remarkable for being one of the few families of birds that possess a penis. However, the sperm do not flow through a central canal, as in mammals, but rather along grooves on the outside (Gzimek et al. 2004).
Most ducks are monogamous. However, unlike true geese, which generally stay paired for several seasons, most ducks are seasonally monogamous, with pair bonds lasting only until midincubation or hatching of the young (Gzimek et al. 2004).
The males (drakes) of northern species often have extravagant plumage, but that is molted in summer to give a more female-like appearance, the "eclipse" plumage. Southern resident species typically show less sexual dimorphism.
Like the geese, the flight feathers of ducks are molted only once a year, and are lost simultaneously so that flying is not possible for that short period of time (Gzimek et al. 2004). However, most true ducks do molt other feathers (the contour feathers) twice a year (Gzimek et al. 2004). When ducks are in a flightless stage, they generally seek out protected habitat with good food supplies during this period. This molt typically precedes migration.
Some duck species, mainly those breeding in the temperate and arctic Northern Hemisphere, are migratory, but others, particularly in the tropics, are not. Some ducks, particularly in Australia where rainfall is patchy and erratic, are nomadic, seeking out the temporary lakes and pools that form after localized heavy rain.
Despite widespread misconceptions, most ducks other than female mallards and domestic ducks do not "quack." A common false urban legend says that quacks do not echo (Amos 2003).
True ducks are members of the subfamily Anatinae of the family Anatidae. Other groups with the name duck are also located in several other subfamilies within Anatidae. The following places the ducks in the context of the order Anseriformes.
A worldwide group like the ducks has many predators. Ducklings are particularly vulnerable, since their inability to fly makes them easy prey not only for avian predators, but also large fish like pike, crocodilians, and other aquatic hunters, including fish-eating birds such as herons. Nests may also be raided by land-based predators, and brooding females may sometimes be caught unaware on the nest by mammals (e.g. foxes) and large birds, including hawks and eagles.
Adult ducks are fast fliers, but may be caught on the water by large aquatic predators. This can occasionally include fish such as the muskie in North America or the pike in Europe. In flight, ducks are safe from all but a few predators such as humans and the Peregrine Falcon, which regularly uses its speed and strength to catch ducks.
The word duck (from Anglo-Saxon dūce), meaning the bird, came from the verb "to duck" (from Anglo-Saxon supposed *dūcan) meaning "to bend down low as if to get under something" or "to dive," because of the way many species in the dabbling duck group feed by upending (compare the Dutch word duiken = "to dive").
This happened because the older Old English word for "duck" came to be pronounced the same as the word for "end"—other Germanic languages still have similar words for "duck" and "end," for example, Dutch eend = "duck," eind = "end," German ente = "duck," and ende = "end." This similarity goes back to Indo-European—compare Latin anas (stem anat-) = "duck," Lithuanian antis = "duck," Ancient Greek νησσα, νηττα (nessa, netta) = "duck" and Sanskrit anta = "end."
Ducks have many economic uses, being farmed for their meat, eggs, and feathers. Duck is considered a delicacy in a number of cultures.
Foie gras (French for "fat liver") is the liver of a duck (or goose) that has been specially fattened. Foie gras is one of the most popular delicacies in French cuisine and its flavor is described as rich, buttery, and delicate, unlike that of a regular duck (or goose) liver. The technique dates as far back as 2500 B.C.E., when the ancient Egyptians began keeping birds for food and deliberately fattened the birds through force-feeding. Today, France is by far the largest producer and consumer of foie gras, though it is produced and consumed worldwide, particularly in other European nations and the United States.
Confit de canard involves duck being macerated in herbs and salt, cooked in savory broth or fat, and then preserved in rendered fat. Such confits are a specialty of the southwest of France (Toulouse, Dordogne, etc.) and are used in refined versions of dishes such as cassoulet. Although confit of duck or goose are now considered somewhat luxurious products, these dishes were used by peasants as a means to store meats for periods of time without refrigeration.
Ducks are kept and bred by aviculturists and often displayed in zoos. All domestic ducks are descended from the wild mallard Anas platyrhynchos, except muscovy Ducks (DUC 2006). Many domestic breeds have become much larger than their wild ancestor, with a "hull length" (from base of neck to base of tail) of 30 cm (12 inches) or more and routinely able to swallow an adult British common frog, Rana temporaria, whole.
In many areas, wild ducks of various species (including ducks farmed and released into the wild) are hunted for food or sport, by shooting, sometimes by using decoys. From this came the expression "a sitting duck," which means "an easy target."
Ducks have become an accepted presence in populated areas. Migration patterns have changed such that many species remain in an area during the winter months. Spring and early summer months find ducks influencing human activity through their nesting. It is not uncommon for a duck pair to nest well away from water needing a long trek to water for the hatchlings—this sometimes causes an urgent wildlife rescue operation if the duck nested somewhere unsuitable like in a small enclosed courtyard.
The expression "quacks like a duck" is sometimes a short form for "It looks like a duck, it quacks like a duck, it swims like a duck, so it's a duck.," used as proverbial to counter abstruse arguments that something is not what it appears to be.
All links retrieved August 25, 2013.
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