Pigeons:

Feral pigeons cause millions of dollars in damage every year. Their droppings contain uric acid, which is highly corrosive and can deteriorate buildings, statues, vehicles, and rooftops. Nesting debris often clogs gutters and drains, leading to roof and water damage. They are a common cause of issues with HVAC units and other rooftop machinery. Their presence also introduces economic risks such as slip-and-fall liability from droppings, and a negative public image for businesses. Beyond structural damage, pigeon droppings may harbor bacteria, fungi, and ectoparasites that can pose health hazards to humans. Pigeon infestations are not just unsightly—they’re a sanitation and safety risk that require prompt control and exclusion methods.