The mallard (Anas platyrhynchos) is a highly adaptable omnivorous bird and the most common of all “dabbling ducks,” found in nearly any wetland habitat across the Northern Hemisphere. As a dabbling duck, it feeds primarily at the water’s surface or by “up-ending,” tipping its body to reach submerged food without fully diving. This flexibility in foraging behavior allows the mallard to thrive in diverse environments, from remote marshes to city parks. Their broad diet reflects this adaptability, shifting with the seasons and the availability of resources.
Primary Plant-Based Foods
The foundation of the mallard’s diet is plant material, which typically makes up a significant portion of their overall food intake, especially for adult males. They actively seek out a variety of aquatic and terrestrial vegetation, which they consume through grazing or filtering. Aquatic plants such as pondweed, sedges, and grasses are readily eaten, often by stripping the leaves and seeds directly from the stems.
Mallards also rely heavily on seeds, grains, and tubers as a dense source of carbohydrates and energy. They consume the seeds of various plants, including wild rice, smartweed, and millets, often using their specialized bill to filter them from the water or mud. When foraging on land, they will graze on agricultural crops like corn, wheat, and barley, particularly in late summer and winter when these grains are readily available in fields.
Essential Animal-Based Foods
While plant matter provides bulk and energy, animal-based foods are a significant source of protein and other nutrients, especially for growing ducklings and adult females during the breeding season. The protein acquired from these sources is needed for feather growth and egg production. In early life, ducklings may consume up to 91% animal matter, and adult females consume more animal foods than males.
Mallards forage for a wide range of invertebrates in both aquatic and terrestrial environments. Their diet includes the larvae and pupae of various insects, such as midges, caddisflies, and dragonflies, which they locate by dabbling at the surface or rooting in the sediment. They also consume mollusks like small snails and crustaceans such as freshwater shrimp. Occasionally, they will opportunistically eat small vertebrates, including tiny fish, amphibians, or earthworms, especially when these items are easily accessible.
Safe Feeding Practices and Harmful Foods
Human feeding, while often well-intentioned, can severely compromise the mallard’s natural diet and health. Foods like bread, crackers, chips, and other processed human snacks offer minimal nutritional value, being high in carbohydrates and low in the necessary vitamins and minerals. When mallards fill up on these “empty calories,” they neglect to seek out their natural, nutritious foods.
A common consequence of this poor diet, particularly in young birds, is “Angel Wing” syndrome. This condition is caused by a nutritional deficiency, often involving low levels of manganese and vitamins D and E, which causes the wing bones to grow improperly. This deformity causes the last joint of the wing to twist outward, permanently preventing the bird from flying. Furthermore, uneaten human food can pollute waterways, promoting the growth of harmful bacteria and attracting pests.
If people choose to feed mallards, they should offer safe, nutritionally sound alternatives to mimic the birds’ natural diet. Supplemental feeding should be done sparingly, ensuring the birds still have a motivation to forage for the diverse components of their natural food sources. Recommended options include:
- Whole grains like oats.
- Cracked corn.
- Wheat.
- Chopped vegetables, such as defrosted peas, shredded lettuce, or cabbage.