Kicking puffballs

365 Urban Species. #023: Mallard

Urban species #023: Mallard Anas platyrhynchos

The mallard is the world's most common duck. Two facts contribute to this, and each fact is hard to extricate completely from the other. The first is that mallards are, among ducks, the least bothered by humans and their industry. They have less aversion to humans than many birds. The second is that mallards have been domesticated world-wide, and in fact, are the primary domestic duck (the other being the much less populous muscovy duck) found on farms everywhere. Whether city ducks are wild ducks that have taken advantage of human handouts or are descendants of domestic ducks is a difficult question. The answer is, most likely: both.

Many urban mallard flocks show evidence of domestic stock ancestry: any variation from the wild coloration is a hint that domestic ducks escaped or (more likely) were released. Mallard plumage shows the sexual dimorphism (difference between the sexes) typical of many birds: showy males, in this case with brilliant metallic green heads, and cryptic females, all the better for camouflage when incubating the nest. Unlike many other birds, mallard females have louder voices than males. The harsh loud "quack" of the female mallard is probably the single most imitated bird call in the world.