When a large number of birds are attracted into an area to feed, the danger of disease increases. Prevention is always better than a cure, and is the best thing you can do to help the birds.

Most diseases are transmitted by droppings. If contaminated droppings mix with food, the birds run a risk of picking up the infection. Since the contamination can originate either from other birds or from animals (such as rats), it's important to guard against infection from both sources in your garden.