The Mallard (Anas platyrhynchos) is the most familiar and widespread dabbling duck across the Northern Hemisphere. These birds display sexual dimorphism, a significant difference in appearance between the sexes, which allows for easy recognition of the male in its full breeding colors. Understanding the distinct plumage, structural features, and seasonal changes is helpful for identification.
The Iridescent Plumage of the Male
The adult male Mallard, or drake, is instantly recognizable due to its vivid coloration designed to attract a mate. The head and upper neck exhibit a striking, glossy, bottle-green iridescence, which can appear black depending on the light angle. This brilliant head is sharply separated from the rest of the body by a narrow, clean white neck ring.
Below the white collar, the breast is a rich chestnut or reddish-brown, contrasting with the paler gray-brown feathers covering the flanks and back. The rear section of the drake is black, and a defining feature of the tail is the presence of four curled feathers, often referred to as the “drake curl.”
The Mottled Appearance of the Female
In sharp contrast to the male’s bright display, the adult female Mallard, or hen, possesses a mottled brown and tan plumage that provides excellent camouflage. Her feathers are a mix of buff and dark brown, creating a scaled or streaked appearance across her body. This subdued coloration is an adaptation that helps protect her while she is nesting and incubating eggs.
The hen’s head features a darker crown and a distinct dark stripe running horizontally through her eye. The area around her throat and cheeks is typically a lighter, paler brown. While generally smaller and lighter than the male, the hen’s overall shape is similar, defined by a hefty body and a long, broad bill.
Structural Features: Bill, Legs, and the Speculum
Several structural features distinguish Mallards, including differences in bill color between the sexes. The male possesses a smooth, bright yellowish-orange bill that is often tipped with black. Conversely, the female’s bill is darker, generally ranging from orange to brown and marked with dark blotches or spots.
The legs and webbed feet of both sexes are a bright orange. Mallards are classified as dabbling ducks, meaning their large, flattened bills allow them to filter food from the water’s surface.
A unifying feature present on both the male and female is the speculum, a patch of iridescent feathers located on the secondary wing feathers. This patch is a vivid purple-blue and is bordered on the leading and trailing edges by thin white bars. The speculum is highly visible in flight, serving as a reliable identification marker.
Changes in Appearance: Eclipse and Juvenile Ducks
A temporary change in the male’s appearance occurs after the breeding season when he undergoes a complete molt into “eclipse plumage.” This period, typically in late summer, causes the drake to shed his colorful feathers and take on a dull, mottled brown appearance that closely resembles the female. This camouflage protects the male while he is vulnerable, as he loses all flight feathers at once and becomes temporarily flightless.
Even in eclipse plumage, the male can be identified by his bill, which retains its yellowish hue, while the female’s bill remains mottled. Juvenile Mallards initially look similar to the adult female, exhibiting dull, streaked brown plumage. Young males begin to develop their distinct coloration as they mature, with adult plumage typically acquired around six to ten months of age.