Pigeon droppings deface and accelerate the deterioration of buildings and increase the cost of maintenance. Large amounts of droppings may kill vegetation and produce an objectionable odor. Pigeon manure deposited on park benches, statues, cars, and unwary pedestrians is aesthetically displeasing. Around grain handling facilities, pigeons consume and contaminate large quantities of food destined for human or livestock consumption.
Pigeons may carry and spread diseases to people and livestock through their droppings. They are known to carry or transmit pigeon ornithosis, encephalitis, Newcastle disease, cryptococcosis, toxoplasmosis, salmonella food poisoning, and several other diseases. Additionally, under the right conditions pigeon manure may harbor air-borne spores of the causal agent of histoplasmosis, a systemic fungus disease that can infect humans.
The ectoparasites of pigeons include various species of fleas, lice, mites, ticks, and other biting insects, some of which readily bite people. Some insects that inhabit the nests of pigeons are also fabric pests and/or pantry pests. The northern fowl mite found on pigeons is an important poultry pest.
Pigeons located around airports can also be a threat to human safety because of potential bird-aircraft collisions, and are considered a medium priority hazard to jet aircraft by the US Air Force.
Feral pigeons are not protected by federal law and most states do not afford them protection. State and local laws should be consulted, however, before any control measures are taken. Some cities are considered bird sanctuaries that provide protection to all species of birds.
Structures inhabited by pigeons can sustain damage from droppings and harbor disease. The droppings can also make structural surfaces slick and hazardous to walk or climb on.
Washing acidic accumulations of drop-pings to prevent structural damage can cost in excess of $10,000 per year. The longevity of industrial roofing materials can be adversely affected by droppings, resulting in expensive replacement costs.
Employee health claims and lawsuits resulting from diseases or injuries attributed to pigeons can easily exceed $100,000. An integrated pigeon management program incorporating lethal and nonlethal control techniques is well worth the investment when considering the economic damage and health threats caused by large populations of pigeons.