She was not alone. Admittedly, luring birds to feeders where they are forced daily into close contact with not only their own species, but other bird species as well, is extremely unnatural. Free ranging birds, those that depend exclusively on natural foods, may travel in flocks, but these flocks are always moving. Once a food source is depleted, it does not grow back again until the year has gone full cycle. Therefore, the birds are forced to move elsewhere.
Diseased birds fail to keep up with the flock, and epidemics thus naturally prevented.
Our backyard feeders, by crowding birds together, day after day, not only encourages the spread of disease but also produce stress that weakens a bird's resistance. In addition to conjunctivitis, birds can contract salmonellosis, a bacteria similar to that which causes food poisoning in humans, by consuming feces-contaminated seeds. Or they can be exposed to aflatoxin, aspergillus fumigatus, or histoplasmosis, diseases caused by fungus that originates in moldy seed. All of these diseases, however, can prevented if you are willing to follow a few simple rules. First, don't feed birds during hot months.