In Praise of the Ordinary: Mallards

Talk about a plain old "ordinary" bird!

The Mallard (Anas platyrhynchos) may very well be the most common, abundant and widespread duck on earth, and for most non-birders, this bird is synonymous with the word "duck."

Mallards are found on calm, shallow bodies of freshwater across North American, Europe and Asia.  They are the ancestor of many, if not most domestic ducks (except for those descended from the very different-looking Muscovy).  Some wild Mallards even seem to domesticate themselves by taking advantage of handouts at city parks and ponds.  These are birds that just about everyone knows!  But there's more to these Mallards than a penchant for stale bread.  Read on to learn more than you ever wanted to about this common park duck.

Mallards are dabbling ducks, part of a larger group of waterfowl that includes the teals, wigeons, Gadwalls, Northern Pintails and Northern Shovelers, all members of the Anas genus.  Dabbling ducks, also called "puddle ducks," forage in shallow water by upending themselves, positioning themselves vertically with their tails in the air so they can effectively reach aquatic plants, invertebrates, fish and even amphibians at or near the bottom of a pond or other body of water.  Mallards may also forage on land, grazing on lawns and other grasses, picking up seeds and grubbing for roots.  The second broad group of ducks, the diving ducks, includes several genera that prefer deeper water in which they dive for food items; this group includes goldeneyes, scaups, mergansers, scoters, eiders, Redheads, Canvasbacks and Buffleheads.

Sexual Dimorphism in Ducks and Other Birds

Male Mallards are called drakes, while females are known as hens.  Males are the colorful ones, with their yellow bills, and brilliant iridescent emerald heads bordered by a white neck ring.  But females are beautiful in their own right, especially when the sun catches the bright purple-blue patch on their wings.

Species of birds in which the male and female exhibit differences in plumage colors and patterns are said to be sexually dimorphic.  Males are often brightly colored in order to impress the females and attract mates, while females are more drab in color to provide better camouflage and help them blend in with their surroundings while they are tending nests.

In the bird world, the general rule is that sexual dimorphism in a species indicates that they do not share equally in the duties of nesting and raising young, exemplified in Mallards, as drakes go off to join flocks of other males while leaving hens to tend the nest and young.

It is also interesting to note that sexual dimorphism in bird species is correlated with promiscuity; in species where it is common practice for males to mate with multiple females, the males are more brightly colored.  Species that tend to be monogamous during the breeding season are more likely to be be sexually monomorpic, with the male and female looking quite similar in appearance.

Common monomorphic species, like Mourning Doves, Mockingbirds and jays, are monogamous and typically share nesting duties.  Common sexually dimorphic species, like the ducks and hummingbirds, are known for their so-called promiscuity.  In other sexually dimorphic groups, like the finches and wood-warblers, pairs are mostly monogamous, with only some extra-pair mating, but the more drab females tend to do most of the incubating, where her earth-toned plumage helps to conceal her and her eggs from predators.

Attracting A Mate

Male and female Mallards form pairs early in the breeding season, generally in the autumn and winter.  Male Mallards exhibit a variety of courtship and breeding behaviors, which can include rearing up from the water while emitting whistles or grunts (called the "grunt-whistle display"); giving a sharp call while raising both its head and tail (the "head-up-tail-up display"); bobbing its head ("head pumping"); and plunging its chest into the water and flinging water with his bill.  These behaviors are exceedingly entertaining to watch!

Mallards are seasonally monogamous, although it is common for males to pursue other females in addition to their own mate, often resulting in chases and somewhat violent-looking (to humans) forced mating.

Does she look impressed?

Raising Young

Nests are usually constructed on the ground, concealed in vegetation, up to a mile from the nearest body of water.  The female Mallard creates a shallow depression in the earth and lines it with bits of vegetation that she can reach while sitting on the nest.  She lays up to a dozen eggs, which she incubates for about a month, plucking down feathers from her own breast to line and insulate the nest during this stage.  Male Mallards don't stick around during the nesting period, but leave to join a flock of other males.  Sadly, the nesting success rate of ground-nesting ducks like Mallards can be as low as 40 percent in some areas, largely due to predation by mammals like foxes and skunks.

The percocial young leave the nest about a day after hatching (or even sooner, within 13-16 hours) and are able to feed themselves immediately.  Though they are able to walk, swim and feed themselves, female Mallards still tend to their broods closely, often leading them to foraging sites and back to safety.  A young Mallard's first flight usually takes place when they are about 2 months old.

A Note on Molt

After the Mallard's lengthy breeding season is finished in late summer, the ducks undergo an extensive molt in which they replace all of their flight feathers at once in what is known as a synchronous molt.  This process takes about a month, during which time they are rendered temporarily flightless and vulnerable.  (Most birds molt their flight feathers one at a time in order to avoid this period of vulnerability.)  Understandably, molting ducks become quite secretive during this time, and males sport a drab "eclipse" plumage (which is technically ducks' alternate, rather than basic, plumage, for all you molt aficionados out there) that looks similar to that of the females.  Mallards then undergo a second, less extensive molt in fall or early winter, during which time the males regain their distinct coloring.

This photo of a male Mallard was taken in October; he is regaining his splendid emerald head and white necklace.

A Word on Conservation

In the wild, Mallards have a lifespan of five to ten years, and pairs may raise two broods of a dozen or more young each year.  As an adaptable species, they have been successful across North America in the face of great change, and their populations are stable.  Numbers do tend to fluctuate with rainfall, however, and their populations decline with droughts.  Mallards are the most-hunted species of duck in North America, and though their populations seem to be able to hold up under such persecution (and are closely monitored by both state and federal wildlife agencies) lead poisoning is still a concern in heavily hunted areas where birds may ingest spent lead shot.

Other potential threats to Mallards include the regular litany of hazards most other wetland species must face: loss of habitat through wetland draining, oil spills, poor water quality, and pollution from pesticides, selenium and heavy metals like mercury.

An additional threat to Mallards as a species may be hybridization with domestic and feral ducks, both in urban parks and the wild.  In some places, hybridization has occurred to such an extent that it can be difficult to distinguish truly wild Mallards from feral populations.  Go down to your local duck pond and check out the wild variety of ducks found there: most are not pure, wild Mallards, but have been mixed to varying degrees with domestic birds.

P.S.  Please don't feed the park ducks, especially white bread; their systems (like ours!) were not meant to run on white processed foods.  If you must feed the ducks, they are particularly fond of lettuce - and it's safe and healthy for them too!