Mallard ducks feed on fish, amphibians, crustaceans, gastropods, worms, aquatic and land plants, grains, seeds, roots, tubers, and invertebrates, such as dragonflies, beetles and flies. They tend to feed on the surface of the water or on the land, rather than diving into the water for food. Mallard ducks follow an omnivorous diet, meaning they eat plant and animal matter.
The food that mallard ducks eat depends on a variety of factors, such as food competition, their current stage in the breeding cycle, their location and nutrient availability in their habitat. During breeding season, male mallards have been documented eating 37.6 percent animal matter and 62.4 percent plant material. Laying females ate 71.9 percent animal matter and 28.1 percent plant material. Females that were not laying eggs ate 37 percent animal matter and 63 percent animal material.
During cold months and migration periods, mallard ducks eat significantly more plants than meat. Mallard ducks are known to graze for plant matter. They are very social animals, except for when they're in a breeding cycle. They congregate in large flocks, which are known as sords. Although mallard ducks are known for their monogamous behavior, male mallards do seek out other females besides their mates.