Mallard Duck

If you think all ducks are milky white birds quacking in ponds, a Mallard Duck will surprise you. An ancestor of most domestic duck breeds, the males of this species will dazzle you with their vibrant green heads and distinct white collars, while the females sport a mottled brown plumage. Their wings bear a striking blue speculum bordered with white, making them one of the most easily recognizable waterfowls in the world.

Subspecies

There are three known subspecies of the mallard duck:

1.  Wild Duck or Wild Mallard (A. p. platyrhynchos)
2.  Domestic Duck or Domestic Mallard (A. p. domesticus)
3.  Greenland Mallard (A. p. conboschas) – disputed

Description

Length: Body – 50 to 65 cm (20 to 26 inches) Wingspan – 81 to 98 cm (32 to 39 inches) Bill – 4.4 to 6.1 cm (1.7 to 2.4 inches)

Weight: 0.7 to 1.6 kg (1.5 to 3.5 lbs)

Body and coloration:

The male mallard has a striking bottle-green head and a well-defined white collar, demarcating the head from its brown breast and pale gray belly. The female is usually mottled, with feathers ranging from buff to dark brown. Males have a yellowish-orange bill with a black tip, while females have a darker bill. 

Both sexes have a white-bordered, iridescent blue speculum on their wings that sets them apart from other waterfowls.

Distribution

These ducks, often considered invasive in countries like Australia and New Zealand, are found in both the Northern and Southern Hemispheres, with notable abundance in the United States. They are migratory, breeding north of their respective range and moving south for wintering.

Habitat

They inhabit natural, artificial, brackish, and freshwater wetlands, including marshes, swamps, lakes, bays, and ponds, with large amounts of floating, submerged, and riparian vegetation. 

Diet

Mallards are omnivores that consume a wide variety of foods. Their choices are based on various factors like the stages of their breeding cycle, nutrient availability, and intraspecific and interspecific competition. 

They feed on gastropods, arthropods, crustaceans, insects, and various aquatic and terrestrial vegetation, such as sedges, grasses, pondweeds, and smartweeds. Besides obtaining underground plant matter like seeds, tubers, and rootlets, they also acquire food from land surfaces. 

Behavior

1. They search for submerged food through a characteristic ‘dabbling’ movement that includes bobbing its head into the water’s surface and quickly out of it. They also poke the soil for underground plant matter when grazing on land. 
2. After the breeding season, mallards migrate southward in flocks, forming the characteristic V pattern. They fly great distances at about 55 miles per hour, taking cues from rivers, coasts, and valleys, and often rest at the same spot every year.
3. The familiar quacking of ducks usually comes from the female mallard. It is termed the ‘decrescendo call’ or the ‘hail call,’ mainly because it helps address the ducklings from a distance. Males usually emit a rasping sound, but they start quacking only when involved in a fight.

Lifespan

These birds have an average lifespan of 5 to 10 years in the wild. When in captivity, they can survive up to 10 years.

Reproduction and Life Cycle

They start forming pairs around October and November in the Northern Hemisphere and remain in courtship throughout winter. These pairs are generally monogamous, but the males often engage in ‘extra-pair copulations,’ forcibly mating with other isolated females. 

Around the nesting season in spring, the female is abandoned at a suitable nesting site while her partner joins the other males to await the molting period, which begins in June. The eggs are laid on alternate days, and the incubation begins when the clutch is nearly complete. About 8 to 13 creamy white to olive-buff eggs are laid in a single clutch. These eggs are free of speckles, measuring about 58 mm (2.3 inches) in length and 32 mm (1.3 inches) in width.

The incubation lasts about a month, with the fledglings hatching at around 60 days. These young are precocial, leaving the nest within a day after hatching, and are led to water by their mother. The ducklings can run and swim at an early stage of their lifecycle. However, they are instinctively driven to stay close to their mother, not only for protection and warmth but also for getting habituated to their surroundings and foraging activities. 

Predators

Their most vicious natural predators are the red foxes and the larger birds of prey. During the breeding season, they are ferociously attacked and displaced from their respective territories by other anseriformes like swans and geese. 

Besides being hunted by humans, mallards are also threatened by mustelids, snakes, skunks, raccoons, raptors, opossums, and owls.

Adaptations

1. Their outer feathers are waterproof and oiled by a secretory gland near the tail. Beneath this repellent layer lies ‘down’ feathers responsible for retaining body warmth.
2. The speckled plumage in females helps them camouflage with their surroundings, thus protecting them against predators during nesting. 
3. As a predator-avoidance behavior, they sleep with an eye open, keeping one hemisphere of their brain active while the other rests.
4. Mallards, like many other sexually dimorphic birds, can go through spontaneous sex reversal when sex organs are damaged or non-functional, thereby causing a female to sport male plumage and vice versa (phenotypic feminization or masculinization.)

Conservation Status

They belong to the ‘Least Concern’ category of the IUCN Red List of Endangered Species. Due to their wide distribution and high adaptability to human alterations, mallards continue to flourish in a world where change is the only constant.

When Mallards colonize an area, they breed with local waterfowl populations, producing viable hybrids. If these hybrids continue to perpetuate, they outgrow the indigenous species population in number, causing their extinction. The global biodiversity of endemic duck species is threatened by this ‘genetic pollution’ in Mallards.

Interesting Facts

1. They shed their flight feathers at the end of a breeding season and remain flightless for about 3 to 4 weeks.
2. According to Cornell Lab, the oldest known mallard, a male, was shot in Arkansas in 2008 when he was at least 27 years and seven months old.