Tuesday, November 1, 2016

Mallard Ducks in Mating Season

Male Mallard duck in mating season. Males are called drakes, females hens.
Ducks molt (shed feathers) twice a year. Males sport these bright colors from
October to March, otherwise the same drab, mottled browns of females.
Only females quack. Only males have the curled tail feathers. 
Mating and reproduction is a prolonged process for Mallard ducks. Males sport their mating feathers - most obviously the bright green head and neck feathers - starting in fall and all winter long. This is the time when ducks pair up. Ducks do not carry over the same pairing from year to year (unlike swans), but during the course of one mating and egg laying season, attempt to be a monogamous couple.

The key word is "attempt." Males do not contribute to nest-sitting time nor care for offspring. Due to higher predator risks to females from their nesting on land and during weeks of care of ducklings, adult males outnumber females by 10 to 25 percent. Unpaired males will pursue paired females and attempt to forcibly mate with them. Paired males will defend their mates, but also briefly leave to force mating on other females. Females try to escape non-pair mating. Despite the best efforts of paired couples, genetic analysis has shown that many broods  - typically 8 to 12 ducklings hatching from eggs laid at one to two day intervals - contain ducklings sired by multiple male parents.

Eggs hatch in a month. The newly hatched ducklings are precocial, meaning hatching with downy feathers, eyes open, and capable of moving about on land and on water within hours after hatching. From birth to fledging - the completion of growth of adult feathers that allow the young birds to fly - takes two months. During this period the ducklings stay close to their mother. From her, they learn where to feed and how to hide from predators. Predation is high. In addition to predator birds such as hawks, ducklings are at risk from herons, snapping turtles and even large fish. Those that survive reach adult weight of two to three pounds in three to four months and will be able to breed next year. In the wild, Mallards may live five to ten years; in captivity can exceed twenty years.

Mallards - like geese and swans - are "dabblers," meaning that they bottom feed in shallow water by dipping head downward, tilting tail up. Other duck species and distant relatives such as loons are by contrast "divers," spending 10 to 40 seconds at a time completely submerged. What Mallards are eating when head down is everything: water plants (greens and roots), insect larvae, tadpoles, snails, small fish... Like Canada geese, Mallards will also land-feed on seeds and farmers' crops such as wheat and barley. Prior to and during egg-laying season females will shift to a higher percentage of animal matter because of the need for a higher protein diet. Keep in mind that a clutch of eggs - laid over two weeks - can be as much as half the mother's body weight.

As everyone who has ever visited Maynard's Farmers Market knows, ducks are happy to eat any bread people are willing to cast on the waters of the mill pond. Yes, they are happy to eat bread. No, they don't need it. Bread does not provide all the vitamins and minerals they require, and feeding birds teaches them bad habits. (When ducks learn to fly toward people it does not always end well.) Junk food once a week will not put the ducks in harm's way. Daily feeding will. Keep in mind that the mill pond and neighboring waters contain far more to eat than the birds can ever consume.

Internet download. Click on photos to enlarge.
Do people shoot ducks? Yes, but not so much in Massachusetts. According to flyways.us, the Mallard population in North America - migrating between the US and Canada - is estimated at 11.8 million. During the 2015 hunting season 3.4 million were reported killed by licensed hunters. The count for our state was around 5,000. Back in the day, our own American Powder Mill, located on the Maynard/Acton border, sold smokeless gunpowder under the brand "Dead Shot." The brand's image was a male Mallard duck falling from the sky.

By the way, lead shotgun pellets have been banned in the U.S. for more than twenty years, reducing by millions the numbers of waterfowl suffering from lead poisoning, either from surviving being wounded, or from fallen pellets being swallowed by bottom-feeding birds.  

In late spring adults molt (shed their feathers). Males forego their mating coloration for the summer, adopting the same drab browns as females until the fall molt, when they get gaudy again.

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