Looking into the causes and the means of preventing or reducing outbreaks of the diseases, they have identified backyard-feeding stations as playing a significant role. There are five diseases associated with bird feeders, all of which can lead to death directly, or indirectly because the birds are more vulnerable to weather, poor nutrition and concurrent infections. The causes of the diseases are food and water contaminated by mold, fungus and infected feces, and surfaces contaminated by viruses from other sick birds. We can recognize sick birds because their feathers look unkempt, and they are less alert, less active, feed less, and are often reluctant to fly away. You can prevent or reduce disease problems at your feeders by taking the following measures.
Every few days clean up waste food and droppings from the ground.
A shovel and broom work well for this. Avoid crowding by providing ample feeder space. Use feeders that don't have sharp points or edges. Bacteria and viruses on contaminated surfaces infect healthy birds through even small scratches. Clean and disinfect feeders once or twice a month, and more often if you observe sick birds.