The Mallard is one of the most common ducks worldwide. Native to much of the Northern Hemisphere, it has been introduced in several places elsewhere in the world. Many domestic ducks are varieties of Mallard that have been bred for captivity and consumption.Like many birds, the females of the species are more drab looking than the males. However, few birds have as stark of a difference as Mallards do. To the untrained eye, they look like they may be different species of duck. In fact, the female Mallard is easy to confuse with the American Black Duck even to trained eyes. However, both male and female Mallards have a common trait in their wings. The speculum (bright coloration on the secondary flight feathers) looks the same in both sexes. It is a patch of iridescent green with which on both the leading and trailing edges. The American Black Duck does not have this white aspect.
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