Ducks are commonly observed on or near bodies of water, leading many to assume they lay their eggs directly within aquatic environments. However, this is a misconception. Ducks do not typically lay their eggs in water. Their eggs require a stable, dry environment for proper development, and while ducks are highly adapted to water, their reproductive strategy involves land-based nesting. The appearance of duck eggs in water usually indicates an unusual circumstance rather than a natural nesting behavior.
Where Ducks Build Their Nests
Ducks primarily construct their nests on land, often in concealed locations close to a water source, providing easy access to food and safety for the ducklings once they hatch, while keeping the eggs secure during incubation. Common nesting spots include dense vegetation, tall grasses, shrubs, or even elevated areas like tree cavities or building rooftops. The female duck, known as a hen, meticulously builds her nest using available materials such as vegetation, leaves, and twigs. As she lays her clutch, typically one egg every one to two days, she lines the nest with down feathers plucked from her own breast. This feather lining serves as insulation, helping to maintain a consistent temperature for the developing embryos, and also provides camouflage when the hen briefly leaves the nest.
Reasons Eggs Might Appear in Water
Although ducks do not intentionally lay their eggs in water, various situations can lead to eggs being found there. One common reason is nest flooding, where a sudden rise in water levels due to heavy rains or overflowing bodies of water submerges or washes away an established nest. Eggs can also be dislodged from a nearby nest by strong winds, currents, or accidental disturbance from animals or humans. Predation attempts can result in eggs being dropped into the water by a predator that is startled or attempting to carry them away. Additionally, some ducks, particularly those with a weak nesting instinct or those that are stressed, might drop eggs indiscriminately, occasionally into water bodies, rather than in a prepared nest.
Why Submerged Eggs Don’t Hatch
Duck eggs found submerged in water are highly unlikely to hatch. A primary reason is the lack of proper gas exchange. Eggshells are porous, containing thousands of microscopic pores that facilitate the diffusion of oxygen into the egg and carbon dioxide and water vapor out, which is essential for the embryo’s respiration and growth. When an egg is submerged, water blocks these pores, cutting off the necessary airflow and effectively suffocating the developing embryo. Prolonged submersion can also lead to bacterial contamination. The porous shell can also permit water and bacteria to enter the egg, leading to infection and spoilage of the embryo. Maintaining a stable temperature is important for embryonic development, and cold water can rapidly chill the egg, preventing the embryo from developing or causing its death. While duck eggs possess a protective outer layer called the bloom, which offers some defense against bacteria, prolonged exposure to water can compromise this barrier.