An adult swan eats about 4kg of aquatic vegetation every day. It reaches these underwater plants by plunging its long neck into the water, or 'upending', tail in the air. To help with the digestion of these plants in its gizzard, or second stomach, the swan swallows grit which grinds up the food.
As well as eating water plants, the swan may also graze on grasses and grains it finds in fields of cereal crops. Sometimes it may eat small fish, frogs and insects.