The rock pigeon (Columba livia) — the common city pigeon — is one of the most widespread and economically costly pest birds in the world. Originally domesticated from wild cliff-dwelling doves in the Mediterranean, feral pigeons have thrived in urban and suburban environments globally for centuries. In Montana, pigeon populations are concentrated in cities and towns like Missoula, Billings, and Great Falls, where buildings provide the ledge and cavity habitat that mirrors their natural cliff-face roosting instincts.
Pigeons are strongly site-faithful — they return to the same roost and nesting sites year after year, and once a flock establishes itself on a building, voluntary departure is extremely unlikely. A pair of pigeons can produce up to six broods per year, with young birds reaching reproductive maturity in six months. This means a problem of a few birds can become a problem of dozens within a single season.
Their droppings are the primary concern: acidic, voluminous, and potentially disease-laden, pigeon waste accumulates rapidly on ledges, rooftops, HVAC equipment, solar panels, and vehicles. The cleanup alone — for a commercial building that has hosted a pigeon flock for several years — can run into the thousands of dollars.
Size
11–13 inches
Color
Gray with iridescent neck; variable coloring in feral populations
Active Season
Year-round
Risk Level
High (disease, structural damage, persistent fouling)
Habitat
Building ledges, rooftops, bridges, parking structures
Reproduction
Up to 6 broods per year
SIGNS OF INFESTATION
Signs You Have a Pigeon Problem
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Visible roosting birds — Groups of pigeons consistently present on specific ledges, rooflines, or window air conditioner units.
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Heavy droppings accumulations — White-gray droppings building up on ledges, vehicles, sidewalks, and around building entrances.
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Cooing and wing noise — Persistent cooing sounds from above, particularly in the morning.
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Nesting material — Untidy piles of twigs, straw, and debris on ledges or in roof corners where nests are being constructed.
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Feathers and debris — Loose feathers and nesting debris accumulating in gutters, on AC units, and on flat rooftop areas.
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Staining and streaking — Dark streaks on building facades below roost sites from droppings washing down in rain.
HEALTH RISKS
Pigeon droppings and nesting material can carry over 60 documented diseases and ectoparasites. Of particular concern are Cryptococcus neoformans (a fungus causing cryptococcal meningitis), Histoplasma capsulatum (histoplasmosis), Salmonella, and Chlamydophila psittaci (psittacosis, a bacterial pneumonia). Pigeon nests also harbor pigeon mites, which can infest buildings and bite humans when the birds are absent. Workers cleaning up heavily soiled roost sites are at greatest risk and should always use PPE including respirators.
PROPERTY DAMAGE
Pigeon droppings are among the most corrosive biological substances in urban environments. They accelerate the deterioration of concrete, stone, metal, roofing membranes, and painted surfaces. Nesting in gutters causes blockages and subsequent water damage. Nesting and roosting on HVAC equipment clogs filters, reduces efficiency, and can cause premature equipment failure. Solar panels fouled by pigeon droppings lose efficiency and are expensive to clean safely. For commercial property owners, the deferred cost of unmanaged pigeon infestations is substantial.
