Summit Outside: Mallards: The ancestors of most domestic ducks
October 27, 2012
Mallards are a pretty commonly seen duck. There are a number of pairs that have raised their young on Dillon Reservoir this summer, and I recently watched a group feeding by “dabbling” on vegetation near the shore not far from Frisco Bay Marina. Mallards are “dabbling ducks” – they feed in the water by tipping forward and grazing on underwater plants: bottoms up!
As a child I had a picture book: “Make Way for Ducklings.” It was the winner of the 1942 Caldecott Medal for its illustrations. It is the story of a pair of mallards who decide to raise their family on an island in the lagoon in Boston Public Garden in Massachusetts. I grew up within walking distance of the public gardens in Boston.
The mallard exists throughout the temperate and subtropical Americas, Europe, Asia and North Africa, and has been introduced to New Zealand and Australia. They can be found from Arctic tundra to subtropical regions in both fresh- and saltwater wetlands. They are seen in parks, ponds, rivers, lakes and estuaries, as well as shallow inlets and open sea within sight of the coastline. They prefer shallow water depths of less than 3 feet and are attracted to bodies of water with aquatic vegetation.
The male bird, called a drake, is an attractive duck with a glossy green head and grey on wings and belly. The females have mainly brown-speckled plumage. This species is the ancestor of most breeds of domestic ducks. Mallards can cross breed as well with a number of domestic ducks. On a farm pond one sees evidence of white duck/mallard hybrids.
The mallard is medium-sized, although it is often slightly heavier than most other dabbling ducks. It is 20-26 inches long; the body making up around two-thirds of the length, and it has a wingspan of 32-39 inches. They weigh about 1.6-3.5 lbs.
Mallards usually form pairs in October and November, and stay together until the female lays eggs at the start of nesting season at the beginning of spring. The male then joins up with other males until the molting period, which begins in June. During the short time before this, the males are still sexually active and some of them sire replacement clutches, or forcibly mate with females that appear to be isolated or unattached, regardless of their species and whether or not they have a brood of ducklings.
When they pair off, often one or several drakes end up “left out.” This group sometimes targets an isolated female duck, even one of a different species, and proceeds to chase and peck at her until she weakens, at which point the males take turns copulating with the female: a kind of gang rape.
The nest is usually on a bank of a body of water, but may not always be near water. When seeking out a suitable nesting site, the females seek areas that are well concealed and inaccessible to ground predators. This can include nesting sites in urban areas such as roof gardens, enclosed courtyards and flower boxes on window ledges.
The nesting period can be very stressful for the female since she lays more than half her body weight in eggs. The clutch of eight to 13 eggs is incubated for 27-28 days to hatching.
Upon hatching, the plumage coloring of the young duckling is yellow on the underside and face with streaks by the eyes, and black on the backside. Once it is one month old, the duckling’s plumage will start looking more like the female, though its plumage is more streaked. At 6-10 months of age, the plumage of female juveniles remains the same while the plumage of male juveniles slowly changes to its characteristic colors. Mallards reach adulthood at 14 months and the average life expectancy is 20 years.
The ducklings are fully capable of swimming as soon as they hatch. They imprint and stay near the mother for warmth, protection and to learn about and remember their habitat and how and where to forage for food. The juvenile can begin flying between three to four months of age.
When ducklings mature, they will learn their traditional migratory routes. Juveniles and their mother may either part or remain together until the next breeding season arrives.
The mallard is highly gregarious outside of the breeding season and forms large flocks, which are known as “sords.”
They can be quite noisy: the male has a nasal call, and a high-pitched whistle, while the female has a deeper quack stereotypically associated with ducks.
The mallard is omnivorous; the diet seems to include butterflies, dragonflies, crustaceans, worms, frogs, many varieties of seeds, plant matter, roots and tubers. Plants generally make up a larger part of the diet, especially during autumn migration and in the winter. They feed by dabbling for plant food or grazing.
Mallards of all ages, especially young ones, have a wide diversity of predators including raptors, crows, snakes, raccoons, opossums, skunks, turtles, large fish and cats and dogs. The dangerous natural predators of adult mallards are red fox and hawks.
Unlike many waterfowl, mallards have benefited from human habitation. They are very adaptable, being able to live and even thrive in urban areas. I once saw a pair of mallards stroll into a retail store along the The Riverwalk in San Antonio and waddle up and down the aisles as if they were shopping.
Since 1933, the Peabody Hotel in downtown Memphis, Tenn., has maintained a tradition of keeping a mallard drake and four mallard hens, called “The Peabody Ducks,” as a popular hotel attraction and guests of honor.
Joanne Stolen is retired from teaching microbiology at Rutgers University.