Starling roosts are a frequent problem in urban areas because of noise, filth, odor and related health concerns. Starlings also compete for nesting sites with native cavity-nesting birds such as bluebirds, flickers, woodpeckers and purple martins. Except for the last three, these diseases rarely infect humans, but may be serious if not diagnosed promptly. Salmonella is found in about 2 percent of pigeon feces and is statistically the most frequent cause of salmonella food poisoning in humans. Histoplasmosis and cryptococosis are systematic fungus diseases which may be contracted by cleaning up dusty bird manure.
Some bites cause welts and skin infection.
Bird droppings deface and accelerate deterioration of buildings and automobiles and land on unwary pedestrians. Bird feces is a common contaminant of grain destined for human consumption. Nests may clog drain pipes, interfere with awnings and make fire escapes hazardous. To control large-scale urban bird problems, it is necessary to understand population control as a management technique. In good habitats abundant animal species recover quickly from the loss of individuals.