The male mallard has a bright green head, grayish brown plumage, and a bright yellow bill. The female is a drab mottled brown color. The male makes a low-pitched raspy sound, while the female makes the familiar "quack." | The male mallard has a bright green head, grayish brown plumage, and a bright yellow bill. The female is a drab mottled brown color. The male makes a low-pitched raspy sound, while the female makes the familiar "quack." |