Do ducks harm people or property?
While ducks do not attack people, they tend to gather in flocks, and the damage they do to property may be considerable. Yards, fields, public parks, ponds, and water reservoirs become damaged by massive amounts of duck feces. The droppings make open spaces, ponds, and sporting fields unpleasant or unsuitable to human use. More serious problems arise when droppings contaminate ponds and other water sources.
Flocks of ducks also create safety issues at airports and roadways by blocking traffic. Mallards are known to transmit diseases, such as duck plague and fowl cholera, to other waterfowl, which makes them a danger to other native populations of birds and livestock.