Fascinating Facts About Nesting Ducks
Tyler Shoberg, Associate Editor on 05/13/2014
The life cycle of a duck seems straightforward: Start out as an egg (let’s skip the debate on which came first), hatch into a duckling, and hopefully, live long enough to fly south, find a mate and start the cycle anew.
Dig a little deeper, however, and the world of nesting ducks is far more complex. And interesting, too. Consider these facts.
Counting Calories: While puddle ducks, such as mallards, feast on corn and waste grain in fall, they switch to high-protein foods in spring. Insects, freshwater shrimp and other invertebrates that thrive in seasonal wetlands stockpile a hen’s fat reserves, the calories she uses almost exclusively during egg laying and incubation.
An Egg a Day: A nesting duck typically lays one egg per day until she has accumulated a full clutch. Hens that lose the first nest will commonly renest a second, third or even fourth time. The later in the summer, however, the fewer eggs a renesting hen’s final clutch will hold.
Last-Ditch Effort: When flushed from a nest, a hen often performs an unsightly maneuver: she defecates. Although it was widely believed hens did this to dissuaded predators, Delta Waterfowl president Frank Rohwer has a much simpler explanation. “A female waits as long as possible to flush, and in the process she flushes really hard and poops. It’s reactionary. They do the same thing when you shoot at them and miss.”
Mom on the Move: During the laying period, hens visit their nest for about an hour a day to lay eggs and work on nest construction. After the clutch is complete, incubation begins and lasts for the next three or four weeks — a time in which a hen only leaves for an hour each morning and afternoon.
Forced Adoption: The act of laying eggs in other female’s nest — nest parasitism — is well documented in waterfowl, and no duck is more notorious than the redhead. A study published in the early 1990s estimated up to 50 percent of all redhead ducklings hatched annually came from nests other than that of their biological mother. And the most common nest for hen redheads to dump an egg? A canvasback’s.
Undercover: Once she has constructed a nest bowl, a hen will cover the eggs with nest material whenever she voluntarily leaves. This protects eggs from temperature extremes, as well as from the hungry eyes of predators.
Well-Timed Hatch: A hen does not incubate during the laying stage, thus no embryonic development occurs. Not only does this mean inclement weather has very little effect on the clutch (a hard freeze of flooding are exceptions), but all viable eggs will hatch within 12 to 24 hours of one another despite being laid days apart.
Lame Duck: As hatch date approaches, a nesting hen might feign injury if she is disturbed in hopes of drawing the attention of predators. Once she feels safe, the hen miraculously is healed and returns to her nest, no worse for wear.
Hole, Sweet Home: Although artificial wood duck houses would lead many to believe they are the sole proprietors of tree-high abodes, the ubiquitous squealer is not the only duck at home in a hole. Other North American cavity nesters include black-bellied whistling ducks, common and Barrow’s goldeneyes, buffleheads and hooded and common mergansers.
Hedge Their Bets: The earlier a hen is disturbed in the nesting process, the greater the chance she will abandon the nest. Later into laying, and especially into incubation, a hen will stick around to the bitter end. If the eggs are pipping, a sign they’re about to hatch, “You literally have to kick a duck off her nest,” Rohwer said.
Lip Service: When biologists are locating and studying duck nests, they are keenly aware of abandonment, especially during the laying stage. If a hen hasn’t laid her egg for the day, she’s more likely to return to her nest. Biologists check for this by touching eggs to their lips. If they find she hasn’t laid today’s egg, biologists will sneak away and give her space.
Island Masters: During extensive studies, Rohwer and his team discovered that mottled ducks are incredibly good at guessing elevation, and will avoid nesting on shallow islands that flood regularly from spring tides. There aren’t vegetative differences on the islands, so it’s anyone’s guess as to how the ducks know which islands will be high and dry weeks later compared to one that will be under water.