Mallard (55–62cm, 22–25in)

The Mallard (Anas platyrhynchos) is a ubiquitous and well-known species of duck that can be found throughout Europe, inhabiting a wide range of aquatic environments from secluded streams to urban boating lakes. Mallards are often habituated to human presence and may approach people without fear.

This large-headed and long-billed dabbling duck is known to interbreed with domesticated ducks, resulting in a variety of hybrid offspring. However, pure Mallards are easily identifiable, especially the male, and even the brown female can be distinguished from other dabbling ducks due to their size. The female Mallard is known for her characteristic "quack quack" call, while the male produces a low nasal whistle.

The female Gadwall (Mareca strepera) is the most likely species to be mistaken for the female Mallard. However, Gadwalls are smaller, slimmer, and more streamlined than the portly Mallard, and have a distinctive white speculum visible from any angle. The bill of the Gadwall is also a key identification feature, with a dark grey top and yellowy-orange sides.

The female Mallard exhibits a range of variations in appearance while typically sporting a brown head with a darker crown and a dark line through the eye. The upper and underparts display a variegated pattern of brown and black. The bill is typically dark brown with orangey edges. On the other hand, the male Mallard is easily recognizable by its bottle-green head, which is separated from the rusty-brown breast by a distinct white neck ring. The bill is a bright banana-yellow color, and both sexes have black eyes and orange feet.

In avian observations, the male Mallard (Anas platyrhynchos) exhibits a distinctive bulbous green head atop a lengthy rusty neck during flight. The upperparts of the male are predominantly greyish, with a black rump "wedge" and white tail. A purple speculum is visible on the rear wing, with two white wing bars. The female, when viewed from above, appears brown and black with a dark tail, white wing bars, and dark speculum.

One common behavior observed in Mallard ducks is their tendency to upend in search of food. The male Mallard can be easily distinguished by his distinctive orange legs and striking black and white rear end. Meanwhile, the female Mallard is characterized by a white edge on her tail and blackish spots on her undertail.

During the summer season, the Mallard species undergoes significant changes in appearance. Male Mallards in eclipse plumage exhibit a pale brown head with a black crown and eyestripe. The upperparts of the male Mallard change to blackish-grey, except for the paler flight feathers, while the rusty-brown breast becomes scalloped black. The bill of the male Mallard also becomes dull greyish-yellow. On the other hand, female Mallards in June to September experience relatively minor changes in appearance, with their crown getting darker, and their upperparts becoming more uniform in tone.