"Humane control of nuisance birds and bird droppings   For property owners, bird control can be a significant problem. Feral birds (particularly pigeons, seagulls and starlings) can be a real nuisance. Without effective bird control, birds can cause a variety of problems, including: Damage to buildings (including blockage of rainwater systems) Property defacement (especially architectural features)  Health hazards (from bird diseases such as ornithosis, cryptococcosis)  Accident hazards (people could slip on droppings or guano) Personal safety hazards  (such as attacks by territorial seagulls) Increased Maintenance Costs  Loss of goodwill."