Birds may gain access through broken tiles & damaged ridge capping. This is usually a seasonal occurrence when birds are about to lay eggs.
Bird droppings may deface buildings & footpaths, rendering surfaces slippery and causing pedestrian and work safety issues. They may also contaminate stored food products (e.g. salmonella).
Bird droppings cause fungal diseases such as Histoplasmosis, Cryptococcosis and Aspergillosis. The spores from these may be inhaled by those nearby, causing symptoms similar to those of influenza.
Nesting in guttering and down-piping often causes water overflow and moisture problems in walls. Their faeces may also cause corrosion in some types of metal guttering. Birds become pests on aerodromes because of the large areas. They are a problem to propeller-driven aircraft, but a great hazard to jet aircraft, where they can be sucked into the jet engines on take- off & landing..