The Mallard duck (Anas platyrhynchos) is the most common and recognizable waterfowl species across the northern hemisphere. Female Mallards employ a deliberate, cautious strategy when choosing a place to lay their eggs, prioritizing optimal concealment and protection from predators. This species is remarkably flexible, leading them to choose a variety of sites that prioritize security for the developing clutch.
Preferred Nesting Location
Mallards typically select a nesting location on the ground, seeking dense, protective cover near a water source. In natural settings, this usually means thick vegetation along the edges of marshes, riverbanks, or ponds, such as tall grasses or thickets of shrubs. The female’s mottled brown plumage blends seamlessly with the surrounding earth, providing effective camouflage while she sits on the nest. They prefer dry land for the nest itself, often concealing it under overhanging plants.
The Mallard’s impressive adaptability allows it to thrive in urban and suburban environments. This flexibility leads hens to choose unexpected, yet concealed, sites far from traditional wetlands. Urban nests have been documented in window boxes, flower pots, under patio furniture, or even on roof gardens. These unconventional locations are often chosen to escape common predators like raccoons and coyotes, or to avoid aggressive male ducks near the water.
Choosing a site far from the water introduces a significant challenge once the ducklings hatch. Mallard ducklings are precocial, meaning they are covered in down and can walk and swim within hours of hatching. The mother must lead her brood on an overland journey to the nearest safe water body. This trek can sometimes span a mile or more and requires crossing roads or navigating populated areas.
Nest Construction and Materials
The process of creating the nest begins with the hen forming a shallow depression on the ground. This initial hollow, often called a “scrape,” is made by pressing her body into the moist earth or existing vegetation. The hen does not carry materials from a distance but instead pulls nearby plant matter toward her while seated.
The first structural lining consists of readily available materials like grasses, leaves, twigs, and weeds found surrounding the site. During the egg-laying period, the hen continues to build up the rim of the nest bowl with this vegetation. The finished nest is typically bowl-shaped, measuring about a foot in diameter, with the central depression four to nine inches across.
The final, softest layer is composed of down feathers that the hen plucks directly from her own breast. This specialized down is added only after the hen has begun incubation, serving two functions. It provides an insulating layer that keeps the eggs warm while she is sitting. Also, the hen pulls the down over the eggs when she leaves the nest briefly, concealing the clutch and helping to maintain their temperature.
The Egg Laying and Incubation Timeline
Mallards begin their nesting season in early spring, with timing ranging from March through early summer depending on the local climate. The hen typically lays a clutch of 8 to 13 eggs. The eggs are a pale color, described as creamy white, grayish, or greenish-buff, and are generally spotless.
The female lays one egg every day or every other day until the full clutch is complete. During this laying period, the embryo’s development is paused. The hen only begins constant incubation once the last egg has been laid, ensuring that development starts simultaneously across the entire clutch.
The incubation period for Mallard eggs lasts approximately 27 to 28 days. The female is the sole incubator, sitting on the nest for most of the day and only leaving for short periods to feed and drink. Because incubation begins together, the ducklings hatch almost simultaneously, typically within a 12- to 24-hour window.