The Mallard duck (Anas platyrhynchos) is one of the most widely recognized waterfowl species, often found in ponds and wetlands across the Northern Hemisphere. The coloration of the Mallard depends entirely on the bird’s sex, age, and the time of year due to sexual dimorphism. This difference in appearance between the male (drake) and the female (hen) is most pronounced during the breeding season. During this time, the male exhibits vibrant display colors while the female maintains a subdued, camouflaged look.
The Brilliant Colors of the Drake (Male)
The breeding male Mallard is known for its spectacular plumage, designed to attract a mate. The head and upper neck display a brilliant, iridescent bottle-green that changes slightly in color depending on the angle of the light. A crisp white neck ring sharply delineates this glossy hood from the rest of the body. The breast feathers are a deep, rich chestnut or purplish-brown, contrasting with the pale gray flanks and back. The tail includes four distinctive, tightly curled black feathers known as “drake curls,” and the male’s bill is a bright, uniform yellowish-orange tipped with black.
The Subtle Colors of the Hen (Female)
In sharp contrast to the male’s vibrant display, the female Mallard exhibits a muted, mottled brown plumage. This cryptic coloration is a survival adaptation, providing highly effective camouflage while the hen is incubating eggs in a ground nest. Her feathers are a tapestry of various shades of buff, tan, and dark brown, often showing a streaked pattern. The hen’s head is primarily brown, featuring a lighter, buff-colored cheek patch and a darker crown and eye-stripe, which helps break up her outline. The female’s bill is typically a mottled mix of orange and black or dark brown, differentiating it from the male’s solid yellow bill.
The Shared Trait: The Speculum
Despite the dramatic differences in their body plumage, both male and female Mallards share a striking feature on their wings called the speculum. This is an iridescent patch of feathers located on the secondary flight feathers, or remiges. In the Mallard, the speculum is a bright, metallic purple-blue or violet, bordered by thin but distinct white bars. The speculum is a structural color, meaning its brightness comes from the way light interacts with nanostructures in the feathers, rather than from pigment. While often concealed when the duck is resting, the speculum flashes prominently during flight, serving as a species recognition signal.
Seasonal and Juvenile Color Changes
The male Mallard’s vibrant breeding colors are not permanent and undergo a temporary transformation known as the “eclipse plumage.” Following the summer breeding season, the drake molts his showy feathers and replaces them with a duller, female-like brown plumage. This camouflage is protective, as ducks shed all flight feathers during this time and are briefly vulnerable and flightless. During the eclipse phase, the male closely resembles the female but is distinguished by his uniformly yellow bill and the retention of the black and white tail feathers. Juvenile Mallards hatch with downy yellow and black plumage, but soon develop a mottled brown coloration similar to the adult female, gradually acquiring their distinct green head and chestnut chest as they mature, typically around six to ten months of age.