What to feed mallards to support their health and to minimize nitrogen and phosphate excretion?

Feeding mallards is a popular activity worldwide. Bread, which is most commonly fed, is relatively high in carbohydrates and salt and low in calcium and phosphorus, posing potential risks to the duck's health. Because the impact of a feeding ban is often minimal, it is preferable to identify healthier alternatives for feeding the mallards. In addition, these alternatives should have relatively low nitrogen and phosphorus levels to minimize excretion through droppings, protecting the plant diversity in the water. For mallards being fed occasionally, feed materials with a low dry matter, nitrogen, and phosphorus content can be used, such as lettuce, apple, banana, and kale. When human feeding contributes significantly to the total feed intake, it is essential to provide a dietary mixture that meets the nutrient requirements of mallards. An example of such a mixture consists of 20% corn, 5% rapeseed, 9% dried mealworms, 26% apple, and 40% poppy seeds. Feeding kale exclusively could be considered an alternative, but further research into long-term effects is necessary.